Hams have always managed to adapt inexpensive commercial gear for amateur radio use. In decades past we adapted military surplus and used commercial radios. Now in the digital age we can use inexpensive WiFi gear for amateur use. A complete 13cm (2.4ghz) ham station can be purchased for $100 or less (see WiFi Devices below). The station can operate under FCC part 97 on a portion of the 13cm ham band that isn’t used by unlicensed 802.11 WiFi devices. Or the station can be operated under FCC part 15 on 802.11 frequencies and inter-operate with non-ham wireless networks in your neighbourhood.
WiFi RF Spectrum:
Most consumer 802.11 devices, commonly called WiFi, operate in the 2.4ghz (13cm) band. Some WiFI manufacturers make 5.8ghz (5cm) and 900mhz (33cm) equipment. Hams share the 2.4ghz and 900mhz bands with ISM (Industrial Scientific & Medical) devices which includes WiFi devices.:
Unlicensed ISM (FCC part 15): 2400 – 2495 Mhz
Amateur (part 97) 13cm band: 2390 – 2450 Mhz
Hams are the PRIMARY users in the US on 2390mhz-2417mhz and secondary users elsewhere. The ISM band is divided into 11 overlapping 802.11 channels, each 5mhz wide. Channel 1 is centered at 2412mhz. Channel 11 is centered at 2484mhz. An 802.11 RF signal is 20mhz wide, using parts of 5 adjacent channels. So, there are only three non-overlapping channels, 1, 6, and 11. Hams may use WiFi gear under FCC part 97 if they stay within 802.11 channels 1 through 6 so the RF signals will be within the 13cm ham band. Also, some WiFi devices can be changed to use a 5mhz wide signal, at 1/4 the data rates, on frequencies outside the 802.11 channels. For example, Ubiquity (http://www.ubnt.com) outdoor WiFi devices can operate at 2397mhz with a 5mhz wide signal, as suggested by the HSMM 13cm band plan. This is within the PRIMARY portion of the 13cm ham band but not in the ISM band. This should reduce unwanted interference from part 15 devices.
Earlier 802.11b equipment used spread spectrum techniques. Later 802.11g equipment uses OFDM (orthogonal frequency division multiplexing). Most modern WiFi devices will support both 802.11b and 802.11g, automatically adapting to the method in use. WiFi devices can automatically choose different modulation techniques, depending upon signal strength, to achieve higher data rates when RF signals are strong enough. 802.11g devices can choose among BPSK, QPSK, 16-QAM and 64-QAM modulation types, used to modulate each sub-carrier of the OFDM signal. This gives data-rates betwen 6 and 54 mbps (megabits per second). 802.11b modulation gives data rates between 1 and 11mbps.
RF Power levels:
Transmitter power of home WiFi gear is typically around 50mwatt to 100mwatt. FCC part 15 limits transmitter power to 1 watt. There are some inexpensive WiFi devices with 0.4 watt to 1 watt transmitters. Part 15 limits the ERP (Effective Radiated Power) by requiring that the transmitter power be reduced by 1db for each 3db of antenna gain in excess of 6db. So, for example, a WiFi device using an 18 db gain antenna must transmit using no more than 1 watt minus 4db (i.e. 0.397watts). The 4db is calculated from (18-6)/3. Part 97 users have no such antenna restrictions, and transmitter power is limited to the usual 1500watts PEP (for 802.11g which is not spread spectrum). Very high power is a moot point for most hams, since 2.4ghz power amps are expensive. A 10 watt 2.4ghz two-way amp, which includes a receive pre-amp, costs over $800 at this time. However, using a 2.5 foot reflector or yagi antenna with 24db gain, costing about $60, and a 0.8 watt transceiver costing less than $100, hams can achieve an ERP of 200 watts. Such an antenna will have a “beam width” of about 8 degrees, which will reduce interference from other WiFi devices.
2.4ghz propagation distance:
The main disadvantage for hams use of Wifi, as with all microwave communications, is that range is effectively limited to line-of-sight distances. I observe that trees, houses, etc., reduce a 2.4ghz signal by 20db or more. Antennas mounted atop typical 50′ ham towers in my experience provide about 2 to 4 mile range. To achieve 2.4ghz line-of-sight communications over a distance of 24 miles, comparable to the range of a typical ham VHF/UHF repeater, assuming level ground with 50′ tall trees and buildings, you’d need both antennas to be 120′ above ground. This is beyond the ability of most individual hams, although ham clubs can often put antennas above 200′ on existing towers or tall buildings. A 2.4ghz repeater with antenna at 300′ would be needed to provide a 24 mile coverage radius to users with antennas only just high enough for the signal to be clear of nearby trees, buildings, etc. The required antenna height is determined by adding the height of obstructions to the height needed to achieve the desired “radio horizon” distance. Visit http://www.qsl.net/w4sat/horizon.htm and enter the two antenna heights. This calculates radio horizon distance. You must add to this antenna height the height needed to overcome any obstructions in the signal path. When considering the height of obstructions, it is common to add an additional 10′ to 15′ to keep the entire Fresnel zone free of obstructions.
You must also transmit sufficiently powerful signal to overcome the “path-loss”. The 2.4ghz free space path-loss is about 100db+20log(kilometers). For a 24 mile (40km) path, the path loss is 132db. A 24db gain receiving antenna reduces it to 108db. With a 0.8 watt transmitter and 24db gain antenna, the ERP of the transmitted signal is +50dbm (200 watts). This signal will be 35db above a typical -93dbm noise floor at the receiver. With the WiFi devices I’ve used, any signal stronger than about 20db above the noise provides a reliable connection.
An on-line calculator, provided by ve2dbe and towercoverage.com, will predict the received signal strength between any two points you select on a map. It takes into consideration the frequency, transmitter power, receiver sensitivity, antenna gain, antenna height. It uses terrain elevation map data, vegetation (trees) data, and urban (building) map data. I’ve found this calculator to predict fairly accurately the actual signal strengths I’ve observed. Received signal strength in excess of about -75dbm usually is sufficient for the WiFi equipment I’ve used. You must sign-up for a free account to use this online calculator
Ham WiFi Uses:
Because of the need for line-of-sight, one practical use for WiFi may be the wireless linking of existing analog VHF/UHF ham repeaters. Most ham repeater antennas are at fairly high locations, so maintaining line-of-sight over many miles should be achievable. Assuming level ground and 50 ft obstructions (trees, buildings, etc), two repeaters with antennas 200′ AGL have line-of-sight for 34 miles. For 150′ antennas, line-of-sight is 28 miles. The repeater audio would be changed to digital VOIP and sent between repeaters. There is free software (Asterisk, Ekiga, etc) that could be used for this. There would be plenty of bandwidth left over to use for other purposes, such as APRS, etc.
Digital Voice and Digital Amateur TV:
Digital Voice and ATV are easily accomplished with WiFi. A WiFi link provides plenty of bandwidth for digital voice communications without the need for voice data reduction schemes, as are required on D-STAR, P-25 and other narrow-band schemes. Free VOIP software such as Ekiga or older versions of NetMeeting can be used. As you speak into a microphone attached to your computer’s sound card, the software sends it as VOIP data to the receiver’s computer, where it is converted back to audio using that computer’s sound card. The same software can also be used for video links as well as audio. The only difference is that video from a camera is digitized and sent rather than audio from a microphone.
Make use of AMPR IP addresses (44.xx.xx.xx):
In the late 1970s, at a time when IP addresses were not in short supply as they are now, hams were granted a large block of about 16 million IP addresses (44.xx.xx.xx) worldwide, for use in connecting ham radio equipment to and through the internet. This IP block is known as AMPRNet (Amataur Radio Packet Network). See http://www.ampr.org for more information. Sub-blocks are given to each state and major cities. For example, Missouri has block 44.46.xx.xx. States have one or more hams who coordinate use of the IPs. WiFi gear used by hams could make good use of these IP addresses, before someone tries to take them away from hams. IP addresses are now valuable. Microsoft recently paid $7.5 million for a little over half a million IP addresses.
WiFi devices typically don’t have control knobs like a radio. Instead they contain a web-site which is used to control the device from your computer using your favorite web-browser (Internet Explorer, Firefox, Chrome, etc). You normally plug your WiFi device directly into your computer using an ethernet cable, and configure it using your favorite web-browser.
IP addresses are the “call signs” of computer networks. Hams call each other on-air using call signs. Similary, when computers want to talk to each other over a network, they call each other using “IP Addresses”. Each device on a computer network is assigned an IP address, just as each ham operator is assigned a call-sign. Hams usually give the “destination” call-sign and their own call sign at the beginning of each transmission. Each computer MUST give the “desgination” IP address and it’s own IP address (the “source” address) at the beginning of each transmission. Each computer transmission is known as a “packet”. Therefore, to talk to the WiFi device, your computer must know the “IP Address” of the device. For the WiFi device to reply to your computer, it needs to know the IP address of your computer. Unlike ham call-signs, which can only be assigned by the FCC, any computer can assign itself an IP address, provided that IP address isn’t already used by some other computer in the network. Your WiFi device user manual will tell you the factory default IP address of the device. It is typically 192.168.1.1 or 192.168.1.20 or 192.168.1.50. You normally plug your WiFi device directly into your computer using an ethernet cable, and point your web-browser at http://192.168.1.1 (or xxx.20 or xxx.50).
Normally each computer on a network doesn’t choose it’s own IP, but is assigned a unique IP address by one computer on the network acting as a “DHCP server”. Just as the FCC assigns each ham a different call sign, the DHCP server assigns a different IP address to each new computer when it is turned on and joins the network. In your local home network, the router that was provied by your ISP probably acts as the DHCP server. However, after you’ve plugged your computer directly into the WiFI device, your computer is no longer connected to the DHCP server, so it cannot automatically obtain an IP address as it usually does. So you probably need to use the “network connections” icon on your computer’s control panel to manually specify an IP address for your computer. Choose an IP address such as 192.168.1.XX, but don’t choose the same IP as your WiFi device. You’ll also need to specify a network “mask”. Specify 255.255.255.0. If required, specify a “gateway” IP address of 192.168.1.1. After you’ve done this, you should be able to enter “http://192.168.1.1″ or “http://192.168.1.20″ into your web-browser and see the login-page of the WiFi device’s website. Your WiFi user manual will tell you the login name and password to use.
Router vs. Bridge mode:
Each WiFi device can typically be configured either in “router” or “bridge” mode. Your internet service provider probably provided you with a router that your computer connects to. Each single local computer network needs only one router (although more routers are allowed). So you’ll probably want to configure your WiFi device in “bridge” mode, which is usually the default setting. Router mode and computer network routing is beyond the scope of this webpage. Hams most often use WiFi routers in a wireless MESH network (see http://hsmm-mesh.org for example).
In bridge mode, your WiFi device acts much like a ham “repeater”. The “bridge” device will re-transmit any transmission that it “hears”. The bridge records each incoming transmission and then immediately re-transmits it. Unlike your local ham repeater which has one transmiter and one receiver, the bridge has two transceivers, one attached to the ethernet cable and one attached to the antenna. Each incoming transmission on either transceiver is re-transmitted on the OTHER transceiver. So data heard on the wireless receiver are re-transmitted over the ethernet cable, and data heard on the ethernet cable are re-sent over the wireless transmitter. So a pair of wireless bridges, each of which is wired to a computer, act just like a long ethernet cable connected between the two computers.
Access Point vs. Station mode
In a ham VHF or UHF repeater, all users transmit to the repeater and receive the repeater. They don’t communicate “direct” to each other. Similarly, in a WiFi network, there is one WiFi device configured as an “Access point” which acts like the ham repeater. Every other WiFi device is configured as a “station”. Each station communicates only with the Access point.
Just as hams can communicate “direct” with each other, without using a repeater, so can WiFi stations communicate with each other. This is called “peer-to-peer” communications, or sometimes “ad-hoc” networking.
WDS (Wireless Distribution System) mode:
Hams sometimes link nearby repeaters to each other using RF links. Each repeater “forwards” incoming transmissions on to the other repeaters. This provides for a wider coverage area, allowing anyone within range of any repeater to talk to anyone else within range of any repeater. Similarly, a non-standard 802.11 extension called WDS can be used to link several nearby WiFi access points together. One of these “WDS Access Points” is usually connected to the internet. Each other WDS Access Point forwards data between wireless “stations” connected to it and the other WDS Access Points. In this manner, data from any “station” Wifi device uses multiple wireless “hops” between WDS Access Points to reach the internet connection. Each “hop” takes about the same amount of time to send one packet of data to the next hop. So, with 2 hops the effective data-rate is reduced to 1/2, with 3 hops the data-rate is reduced to 1/3, etc. Finally, since WDS is not part of the 802.11 standard, different manufacturers might implement it differently. So there’s no guarantee that WDS will work among devices from different manufacturers.
WIFi MESH networks:
One problem with using WDS is that each time you add a new WDS Access Point you must manually specify to it which other nearby WDS nodes it should forward data to. You must also reconfigure the nearby WDS nodes, adding the newly added WDS node to their list. This slows down rapid deployment of a WDS network, especially when the network must change often to accomodate changing emergency conditions. This manual configuration problem can be eliminated using the HSMM-MESH firmware from http://hsmm-mesh.org. The firmware is uploaded into Linksys WRT54G WiFi devices. When several such devices are deployed as a MESH network, the devices will automatically discover each other, and automatically configure their routing so that data can go between any two computers attached to the network, or between any computer and the internet connection. As MESH network nodes are added and removed, the firmware automatically discovers the changes and reconfigures itself.
The OpenWRT firmware is also popular among mesh network enthusiasts. OpenWRT can be loaded onto many different WiFI devices, including new models with higher powered transmitters designed to be mounted outdoors next to an antenna. OpenWRT is basically a small distribution of the Linux operating system designed to run on the CPU within WiFi devices. It provides many ways to customize your WiFi devices using various application firmware (smart phone users call them “apps”). Among these are the popular B.A.T.M.A.N., OLSR and R.O.B.IN firmware, available for free at http://opensourcemesh.org. These firmware “apps” implement mesh network routing protocols.
In metropolitan areas, there may be two or more ham repeaters on the same frequency within range of a ham with a good antenna. So, ham repeaters use CTCSS to allow each ham to select which repeater he wants to communicate with. To use any particular repeater, each ham configure his radio to use the CTCSS of that repeater. Similarly, each WiFI Access Point chooses an SSID. The SSID can be any word of 32 letters or less. Each WiFi station that wants to talk to the Access Point must use the same SSID as the Access Point.
802.11 WiFi devices may encrypt their transmissions for security reasons. There are two encryption methods to choose from: WEP and WPA (now WPA2). When using encryption, the WiFi Access Point is configured to use a secret word, called a “key”. Every station wishing to communicate with that access point must be configured to use the same key. Hams using WiFi devices under part 97 must disable encryption which is expressly forbidden by the FCC.
Deploying a WiFi device:
Hams usually want to mount a WiFi antenna outside, or at least near a window, so the $20 to $30 USB WiFi devices are not a good idea unless your computer is outside or near a window. There are many WiFi devices designed for home use, often called “Access Points”, in the $30 to $50 range, that have an ethernet connection to your computer instead of USB. These typically have 50mw to 100mw transmitters, and attached antennas about 4 inches long with a gain of about 5db. Due to the excessive losses in long runs of coax cable, hams usually mount the entire WiFi transceiver, including antenna, outside on a roof or tower. In years past I’ve enclosed indoor WiFi devices in PVC weatherproof boxes from Home Depot ($12 to $35 depending upon size). You then run an ethernet cable (Cat-5 network cable) from the WiFi device to your computer. Now days there companies like Ubiquiti and EnGenius make outdoor Wifi transceivers with 500mw transmitters, integrated antennas and “power-over-ethernet” (POE) for $65 to $100. POE eliminates the need to have electric power atop your tower or roof. At these inexpensive prices, there’s no longer any economic reason to build your own weatherproof enclosure or antenna. For example, the Ubiquiti AirGridM2 with 16db reflector antenna and POE is outdoor mountable and costs $65 new.
Some WiFi Devices I’ve Used
The WRT54G has been around for almost a decade. It costs about $35 on ebay these days. It has about 100mw transmitter and a detachable antenna with a reverse polarity TNC coax connector (RP-TNC). Over the years Linksys built 8 versions of WRT54G. The first 4 versions are still popular with hams and others wishing to create a wireless MESH network. The http://hsmm-mesh.org group provides free firmware which can be uploaded into a WRT54G device (versions 1-4 only). Such devices can automatically detect each other if within range, and automatically route data through the network.
See http://ubnt.com for Ubiquiti’s line of WiFi devices. The NanoStation LoCo (100mw) costs about $48. The NanoStation2 (400mw transmitter) costs about $80. Each have a built-in 10db directional antenna. It has a weatherproof case suitable for outdoor mounting. It has power-over-ethernet, so you don’t need electric power at your antenna. Like other Ubiquiti outdoor products, the NanoStation2 uses the Atheros wireless chipset. These chips are capable of operation on additional frequencies in the 13cm ham band that are not allowed for unlicensed WiFi use in the US. Configure the Ubiquiti firmware’s country to “Conformance Test” instead of “USA” in order to gain access to these additional frequencies. Be careful to insure you then select frequencies within the ham band. Also like other Ubiquiti products, you can configure the device to use a 5mhz wide signal (non standard) instead of a 20mhz wide signal. This should provide increased range due to 4x power spectral density, at the expense of reducing the data rate to 1/4. So data rates are between 1.5mbps and 13mbps , instead of 6mbps and 54mbps. Even 1.5mbps is plenty of bandwidth for most ham uses.
The Bullet2 (100mw transmitter) costs about $40 new, and the Bullet2-HP (800mw transmitter) costs about $80 new. The outdoor weatherproof unit is shaped like a cylinder (a bullet) with the N-series male coax connector at one end. This makes it is easy to mount directly to a high-gain antenna which often come with an N-series female coax connector. It uses power-over-ethernet, but you must purchase the power supply separately (about $14). Several 24db gain parabolic reflector antennas, about 24″x39″ in size, are available for about $60 plus shipping. So a complete 13cm ham station with 200 watts (53dbm) EIRP costs only about $154, using your existing tower or antenna mast.
The AirGridM2 (500mw transmitter) costs $65 new and comes with integrated 16db reflector antenna, POE, and antenna mast mounting clamp. Just clamp it to a pole or tower and run cat-5 cable to your ham shack’s computer and you’re on-the-air on 13cm band. A version with a 17″x24″ 20db antenna is available for about $95, providing 50 watts (47dbm) EIRP. That provides a complete 13cm station using your existing tower or antenna mast.
EDUP EP-AB003 8-Watt 2-way power amplifier
The price of 2.4ghz power amplifiers has dropped in recent months from about $200 for a 1-watt amplifier to $59 for an 8-Watt amplifier. I recently tested the EDUP EP-AB003 8-Watt amp (from China) by attaching it to a Linksys WRT54G wireless router. This amount of power is only legal when used with a ham license, on the first 5 WiFi channels which overlap the 13cm ham band. I used a Ubiquiti Bullet, mounted atop a tower about 50 yards away, to measure the Linksys signal strength with and without the amplifier. The Linksys stock antenna (5db) was used without the amp, and the antenna that came with the amp (about 6db) was used with the amp. This antenna is about 1-inch longer than the Linksys antenna, so that may account for 1 or 2db of the gain I observer. Here’s the results of my test:
Linksys without amplifier: -58dbm to -70dbm average -64dbm
Linksys with amplifier: -42dbm to -56dbm average -49dbm (15db increase)
The EP-AB003 specs say the transmit gain should be 17db. My measured 15db is within the error tolerance of my measurements. The amplifier may only be responsible for 13db to 14db of this gain, due to slightly longer antenna. The EP-AB003 input power limits are 3mw to 100mw. I believe the Linksys with stock firmware is about 50-100mw. Assuming 80mw Linksys output and 14db amplifier gain, the amplifier output power was 2.0 watts. The EP-AB003 specs say the receiver gain is 11db with a 3db typical noise figure. The Linksys I used had no way to measure anything about the received signal strength from the Ubiquiti bullet.


16in 9 Pin Serial Male to 10 Pin Motherboard Header Panel Mount Cable
- Turn a Motherboard IDC Serial Header into a Panel-Mountable 9-Pin RS232 Serial Connector
- Fasten a DB9 (RS232) Serial port to an existing face or wall plate
- Add legacy hardware to newer systems
- Provides an industry standard panel mount port for RS232 Serial applications
- Custom design.
|Part number STC-OO003
|Connector A 1 -IDC (10 pin, Motherboard Header) Female
Connector B 1 -DB-9 (9 pin, D-Sub) Male
|ul 2651 9pin flat ribbon cable 28AWG|
|Products Length 16 in [406.5 mm]
Product Weight 0.6 oz [16 g]
|Package Quantity 1
Shipping (Package) Weight 0.8 oz [22 g]
|What’s in the Box|
|Included in Package 1 – 16in 9 Pin Serial Male to 10 Pin Motherboard Header Panel Mount Cable|
The STC-OO003 16-inch IDC Serial to Panel Mount Serial Cable, features a 10-pin (IDC) motherboard header connection on one end and a panel mount DB9 male connector port on the other – a simple answer for adding a DB9 (RS232) serial port to any computer system which has an RS232 serial panel mount receptacle.
This cost-effective solution bridges the compatibility gap between modern computers and legacy serial peripherals.
The Stccabe.com Advantage


The micro:bit is only the size of a card, but it can do a lot of things. It has built-in temperature, light and orientation sensors, as well as Bluetooth device, Micro USB interface. Not only that, it also has a row of pins that can be connected to various sensors. Therefore, the micro:bit can do all kinds of interesting experiments.
The left side of the above picture is the back of the V1 micro:bit board, and the right picture is the back of the V2 micro:bit board.
1.Radio Antennas and Bluetooth Antennas
2.CPU and temperature sensor
6.Micro USB socket
10.USB interface chip
13.Red Power LED
14.Yellow USB LED
15.Reset and power buttons


Each GateHawk Video Intercom comes with the Call A Manager feature for visitors to use. When users interact with this feature, it will dial out a phone call to the number listed on the property contact.
To locate this number follow the steps below.
- Click the Profile tab in the navigation bar to see the My Property Details page.
- Locate the Company Information section.
- Locate the Phone Number item. This is the phone number associated with the Call A Manager feature on the video intercom. To edit this number, use the Edit Property Profile button at the top right-hand corner of the page.
Some best practices for using the Call A Manager feature are listed below:
- Enter a phone number that is accessible by multiple individuals. This ensures visitors calls won't go unanswered when a specific staff member is out of office.
- Train all property staff on the phone system connected to this feature of the video intercom. To allow a visitor access the staff member will be required to press the * (star) key.


Our community now offers the option to send text messages to 911 in the event of an emergency. Important messages about the service:
- If you need help and are unable to speak, use your mobile phone to send a text message to 911.
- 911 dispatchers on duty will respond to texts with the same priority as voice calls to send help as soon as possible.
- When texting an emergency, first send the address or cross streets of the emergency, in order to expedite emergency services to your location.
- Text to 911 eliminates a significant communication barrier for those who are deaf, hard of hearing or speech impaired.
- The service also helps people in dangerous situations where the caller should remain silent or discreet.
- The service works with all major carriers and mobile phones.
- Texts to 911 cannot receive emojis, special characters or multi-media files such as photos, videos or GIFs.
- Texts to 911 that include additional recipients or more than 160 characters will not be received.
- Voice calls to 911 will always be quicker and more efficient, so call if you can and text if you can’t.
When to use Text to 911:
- You’re deaf, hard of hearing or have a speaking disability.
- You’re in a situation when it’s not safe to call 911 for help.
- You’re having a medical emergency and cannot speak on the phone.
Sending a text message to 9-1-1 is easy
- Open a new text message on your mobile device.
- Type 911 in the recipient field.
- Begin your text conversation with the location of the emergency and hit “send.”
Your text message will be received by a dispatch center professional who is trained to respond to your emergency. This new text to 911 option is effective and efficient but calling is the most reliable method. Please remember to call if you can, text if you can’t.


- Hewlett Packard Enterprise Aruba AP-303 RW 867 Mbit/s White
The affordable 303 Series 802.11ac campus access points deliver high performance to medium density enterprise environments such as schools, retail branches, warehouses, hotels and enterprise offices, where the environment is cost sensitive. As a Unified AP, they can be operated with (ArubaOS mode) or without a controller (InstantOS mode).
These Wave 2 access points deliver multi-user MIMO (MU-MIMO) and a maximum concurrent data rate of 867Mbps in the 5GHz band and 300 Mbps in the 2.4GHz band (for an aggregate peak data rate of 1.2Gbps).
With an integrated Bluetooth Low-Energy (BLE) radio, the 303 APs can be used as an Aruba beacon for advanced location and indoor wayfinding, asset tracking, and proximity-based push notification services while simplifying the remote management of battery-powered Aruba Beacons.
Get a big performance advantage
Patented ClientMatch™ technology improves performance and eliminates sticky client behavior while roaming.
Protect service quality over the air
AppRF technology enables prioritization and policy enforcement for business-critical enterprise apps like Microsoft Skype for Business.
Integrated Bluetooth Beacon
An integrated Aruba Beacon delivers location services that can be centrally managed.
|Ethernet LAN data rates||10,100,1000 Mbit/s|
|Maximum data transfer rate||867 Mbit/s|
|Networking standards||IEEE 802.3af,IEEE 802.3az|
|> Ports & interfaces|
|Ethernet LAN (RJ-45) ports||1|
|Number of users||256 user(s)|
|Power consumption (typical)||4 W|
|Output voltage||12 V|
|Power consumption (max)||8.8 W|
|> Operational conditions|
|Operating temperature (T-T)||0 - 40 °C|
|Storage temperature (T-T)||-40 - 70 °C|
|Operating relative humidity (H-H)||5 - 93%|
|> Weight & dimensions|
|Package width||190 mm|
|Package depth||180 mm|
|Package height||60 mm|
|Package weight||410 g|
|> Other features|
|Certification||FCC/ISED CE Marked RED Directive 2014/53/EU EMC Directive 2014/30/EU Low Voltage Directive 2014/35/EU UL/IEC/EN 60950 EN 60601-1-1 and EN 60601-1-2|
|Maximum data transfer rate (5 GHz)||867 Mbit/s|
|MIMO type||Single User MIMO|
|Antenna gain level (max)||5.9 dBi|
|Antenna features||Integrated antenna|
Hewlett Packard Enterprise Aruba AP-303 RW 867 Mbit/s White/shop/product/jz320a-hewlett-packard-enterprise-aruba-ap-303-rw-867-mbit-s-white-1610
Once the user has seen at least one product this snippet will be visible.


Editing WhatsApp messages after they’ve been sent… in testing
Yesterday, Monday, WABetaInfo reported that the WhatsApp instant messaging service continues to develop its new feature that allows users to edit sent messages. We tested one of the most requested features – editing messages – in version 22.23. Apple.
At the time, WABetaInfo stated that the feature would allow users to edit messages within 15 minutes of posting them. Thus, this feature will be useful for correcting any error in messages or adding new information to them before the other party sees them.
And while WhatsApp now allows users to delete any message sent before the other party sees it, the feature is intended for users who don’t want to delete messages, but rather modify their content before they are seen.


Azure Operator Nexus is the next-generation hybrid cloud platform created for communications service providers (CSP). Azure Operator Nexus deploys Network Functions (NFs) across various network settings, such as the cloud and the edge. These NFs can carry out a wide array of tasks, ranging from classic ones like layer-4 load balancers, firewalls, NATs, and 5G user-plane functions (UPF), to more advanced functions like deep packet inspection and radio access networking and analytics. Given the large volume of traffic and concurrent flows that NFs manage, their performance and scalability are vital to maintaining smooth network operations.
Until recently, network operators were presented with two distinct options when it comes to implementing these critical NFs. One utilize standalone hardware middlebox appliances, and two use network function virtualization (NFV) to implement them on a cluster of commodity CPU servers.
The decision between these options hinges on a myriad of factors—including each option’s performance, memory capacity, cost, and energy efficiency—which must all be weighed against their specific workloads and operating conditions such as traffic rate, and the number of concurrent flows that NF instances must be able to handle.
Our analysis shows that the CPU server-based approach typically outshines proprietary middleboxes in terms of cost efficiency, scalability, and flexibility. This is an effective strategy to use when traffic volume is relatively light, as it can comfortably handle loads that are less than hundreds of Gbps. However, as traffic volume swells, the strategy begins to falter, and more CPU cores are required to be dedicated solely to network functions.
In-network computing: A new paradigm
At Microsoft, we have been working on an innovative approach, which has piqued the interest of both industry personnel and the academic world—namely, deploying NFs on programmable switches and network interface cards (NIC). This shift has been made possible by significant advancements in high-performance programmable network devices, as well as the evolution of data plane programming languages such as P4 and NPL. For example, programmable switching Application-Specific Integrated Circuits (ASIC) offer a degree of data plane programmability while still ensuring robust packet processing rates—up to tens of Tbps, or a few billion packets per second. Similarly, programmable Network Interface Cards (NIC), or “smart NICs,” equipped with Network Processing Units (NPU) or Field Programmable Gate Arrays (FPGA), present a similar opportunity. Essentially, these advancements turn the data planes of these devices into programmable platforms.
This technological progress has ushered in a new computing paradigm called in-network computing. This allows us to run a range of functionalities that were previously the work of CPU servers or proprietary hardware devices, directly on network data plane devices. This includes not only NFs but also components from other distributed systems. With in-network computing, network engineers can implement various NFs on programmable switches or NICs, enabling the handling of large volumes of traffic (e.g., > 10 Tbps) in a cost-efficient manner (e.g., one programmable switch versus tens of servers), without needing to dedicate CPU cores specifically to network functions.
Current limitations on in-network computing
Despite the attractive potential of in-network computing, its full realization in practical deployments in the cloud and at the edge remains elusive. The key challenge here has been effectively handling the demanding workloads from stateful applications on a programmable data plane device. The current approach, while adequate for running a single program with fixed, small-sized workloads, significantly restricts the broader potential of in-network computing.
A considerable gap exists between the evolving needs of network operators and application developers and the current, somewhat limited, view of in-network computing, primarily due to a lack of resource elasticity. As the number of potential concurrent in-network applications grows and the volume of traffic that requires processing swells, the model is strained. At present, a single program can operate on a single device under stringent resource constraints, like tens of MB of SRAM on a programmable switch. Expanding these constraints typically necessitates significant hardware modifications, meaning when an application’s workload demands surpass the constrained resource capacity of a single device, the application fails to operate. In turn, this limitation hampers the wider adoption and optimization of in-network computing.
Bringing resource elasticity to in-network computing
In response to the fundamental challenge of resource constraints with in-network computing, we’ve embarked on a journey to enable resource elasticity. Our primary focus lies on in-switch applications—those running on programmable switches—which currently grapple with the strictest resource and capability limitations among today’s programmable data plane devices. Instead of proposing hardware-intensive solutions like enhancing switch ASICs or creating hyper-optimized applications, we’re exploring a more pragmatic alternative: an on-rack resource augmentation architecture.
In this model, we envision a deployment that integrates a programmable switch with other data-plane devices, such as smart NICs and software switches running on CPU servers, all connected on the same rack. The external devices offer an affordable and incremental path to scale the effective capacity of a programmable network in order to meet future workload demands. This approach offers an intriguing and feasible solution to the current limitations of in-network computing.
In 2020, we presented a novel system architecture, called the Table Extension Architecture (TEA), at the ACM SIGCOMM conference.1 TEA innovatively provides elastic memory through a high-performance virtual memory abstraction. This allows top-of-rack (ToR) programmable switches to handle NFs with a large state in tables, such as one million per-flow table entries. These can demand several hundreds of megabytes of memory space, an amount typically unavailable on switches. The ingenious innovation behind TEA lies in its ability to allow switches to access unused DRAM on CPU servers within the same rack in a cost-efficient and scalable way. This is achieved through the clever use of Remote Direct Memory Access (RDMA) technology, offering only high-level APIs to application developers while concealing complexities.
Our evaluations with various NFs demonstrate that TEA can deliver low and predictable latency together with scalable throughput for table lookups, all without ever involving the servers’ CPUs. This innovative architecture has drawn considerable attention from members of both academia and industry and has found its application in various use cases that include network telemetry and 5G user-plane functions.
In April, we introduced ExoPlane at the USENIX Symposium on Networked Systems Design and Implementation (NSDI).2 ExoPlane is an operating system specifically designed for on-rack switch resource augmentation to support multiple concurrent applications.
The design of ExoPlane incorporates a practical runtime operating model and state abstraction to tackle the challenge of effectively managing application states across multiple devices with minimal performance and resource overheads. The operating system consists of two main components: the planner, and the runtime environment. The planner accepts multiple programs, written for a switch with minimal or no modifications, and optimally allocates resources to each application based on inputs from network operators and developers. The ExoPlane runtime environment then executes workloads across the switch and external devices, efficiently managing state, balancing loads across devices, and handling device failures. Our evaluation highlights that ExoPlane provides low latency, scalable throughput, and fast failover while maintaining a minimal resource footprint and requiring few or no modifications to applications.
Looking ahead: The future of in-network computing
As we continue to explore the frontiers of in-network computing, we see a future rife with possibilities, exciting research directions, and new deployments in production environments. Our present efforts with TEA and ExoPlane have shown us what’s possible with on-rack resource augmentation and elastic in-network computing. We believe that they can be a practical basis for enabling in-network computing for future applications, telecommunication workloads, and emerging data plane hardware. As always, the ever-evolving landscape of networked systems will continue to present new challenges and opportunities. At Microsoft we are aggressively investigating, inventing, and lighting up such technology advancements through infrastructure enhancements. In-network computing frees up CPU cores resulting in reduced cost, increased scale and enhance functionality that Operators can benefit from through our innovative products such as Azure Operator Nexus.
- TEA: Enabling State-Intensive Network Functions on Programmable Switches, ACM SIGCOMM 2020 https://dl.acm.org/doi/10.1145/3387514.3405855
- ExoPlane: An Operating System for On-Rack Switch Resource Augmentation, USENIX NSDI 2023 https://www.usenix.org/conference/nsdi23/presentation/kim-daehyeok
The post Unlocking the potential of in-network computing for telecommunication workloads appeared first on Azure Blog.


Faculty of Computer Science
Helsinki University of Technology
The IPv6 address space differs from the IPv4 address space in several ways. There are new address types and the fields of the addresses are assigned different meanings. This paper describes the IPv6 address space as laid out in several Internet RFCs and Internet Engineering Task Force Internet Drafts and also presents some methods designed for address assignment and management.
When IPv6 was in its early stages, one of the main topics of the discussion was how long the IPv6 address should be. The IPv4 address is 32-bit, with a theoretical maximum of over four billion addresses. The hierarchy of the IPv4 address, i.e. network, subnet and host, reduces the actual amount of addresses available. In [HRATIO] Huitema presents what he calls the H ratio for address assignment efficiency. It is calculated with the formula
log (number of objects) H = ----------------------- available bits
In the following examples Huitema uses base 10 logarithms, as that is the more natural way of thinking of large numbers. Thus the H ratio ranges from 0 to 0.30102 (log10 of 2).
To try to figure out how large the IPv6 address space should be, Huitema uses some examples of similar numbering schemes. The focus is on how large the systems grew before they had to be extended to allow new nodes to be added to the system.
With these examples in mind Huitema constructs the following table for the different possible IPv6 address sizes. The numbers express the maximum number of IPv6 addresses.
|bits||Pessimistic (0.14)||Optimistic (0.26)|
An estimate for the number of Internet hosts in the future is 1015. The 64 bit alternative lies below or above the estimate depending on your point of view. The 128 bit address, however, is more than enough. As a matter of fact, if you assign 80 bits of the address to the "network" part and leave 48 bits (the IEEE hardware link layer address length) for stateless address autoconfiguration, you still end up with a reasonable worst case of almost 1012.
The IPv6 addresses are 128 bits long.
An IPv6 address consists of 128 bits, and is usually written as a text string of eight 16-bit hexadecimal numbers. The address itself refers to an interface, rather than a node as in IPv4, and one interface may be assigned several addresses.
Addresses will usually have long strings of zero bits, so a textual
format for compressing zeroes in the address has been devised. One
and only one string of consecutive zeros may be replaced by
|a unicast address|
|a multicast address|
|the loopback address|
|the unspecified addresses|
During the transition period from IPv4 to IPv6, both types of
addresses will coexist on the Internet. IPv4 type addresses in the
IPv6 environment may be written as
In this representation, the IPv4 address is
its IPv6 prefix is
According to [ADARCH] the IPv6 address space will be divided into parts as shown in the following table. 15% of the address space is allocated, the remaining 85% are reserved for future use.
|Allocation||Prefix (binary)||Fraction of Address Space|
|Reserved for NSAP Allocation||0000 001||1/128|
|Reserved for IPX Allocation||0000 010||1/128|
|Provider-Based Unicast Address||010||1/8|
|Reserved for Geographic-Based Unicast Addresses||100||1/8|
|Unassigned||1111 1110 0||1/512|
|Link Local Use Addresses||1111 1110 10||1/1024|
|Site Local Use Addresses||1111 1110 11||1/1024|
|Multicast Addresses||1111 1111||1/256|
Depending on what role an IPv6 node plays in the network, it may have much or little knowlege of the internal structure of the IPv6 address. A host may consider the address to be a contiguous string of 128 bits.
Usually a host will know the link prefix(es) for its link(s) and that part of the address is the interface ID.
|n bits||128-n bits|
|subnet prefix||interface ID|
Hosts on IEEE 802 LANs will probably use an address format similar to this
|n bits||80-n bits||48 bits|
|subscriber prefix||subnet ID||interface ID|
In some cases the network organization that a host belongs to has further partitioned the above subscriber prefix (see Topology).
|s bits||n bits||m bits||128-s-n-m bits|
|subscriber prefix||area ID||subnet ID||interface ID|
0:0:0:0:0:0:0:0 is known as the unspecified
address. It is used to indicate that the address is unknown and must
therefore never be assigned to any node. It is used as source address
during autoconfiguration to indicate
that the host does not know its address. The unspecified address must
not be used as a destination address.
0:0:0:0:0:0:0:1 is the loopback address which
is used by a node to send packets to itself. The address must not be
assigned to any node and must not be sent outside a single node.
There are two kinds of embedded IPv4 addresses. The "IPv4-compatible IPv6 addresses" are used to tunnel IPv6 packets over IPv4 routers.
|80 bits||16 bits||32 bits|
"IPv4-mapped IPv6 addresses" are addresses of nodes that do not support IPv6.
|80 bits||16 bits||32 bits|
The format of provider based unicast addresses is
|3||n bits||m bits||o bits||125-n-m-o bits|
|registry ID||provider ID||subscriber ID||intra-subscriber|
The provider based address format is designed to allow flexible assignment of addresses in a way that makes routing cheap but still allows a multitude of different configurations. [UUALL]
There are two kinds of addresses for local use. The link-local address is used in address autoconfiguration and neighbour discovery (see Autoconfiguration). Routers must not forward packets with link-local source addresses.
|10 bits||n||118-n bits|
Site-local addresses can be used in networks that are not connected to the Internet. If they at some point decide to join the Internet, the site-local prefix must be replaced with a subscriber prefix. Packets with site-local addresses must not be routed outside the site.
|10 bits||n||m||118-n bits|
|subnet ID||interface ID|
Anycast addresses are allocated from the unicast range and are syntactically indistinguishable from unicast addresses (see Anycast).
The IPv6 anycast addresses are taken from any of the unicast address ranges. They differ in the fact that the same address is assigned to several interfaces, which must know that the addresses are anycast addresses. A node sending to an anycast address does not need to know that it is an anycast address.
A packet sent to an anycast address is routed to the "nearest" node that has that address; the measure of distance depends on the routing protocol used. There is little experience of the use of anycast addresses in an internet, and it is expected that the use will mostly be site-local. Routers will respond to several different anycast addresses and in that way support different routing policies.
Currently two restrictions are imposed on IPv6 anycast addresses. [ADARCH]
|n bits||128-n bits|
The IPv4 broadcast address concept has been replaced by multicast addresses. A multicast address identifies a group of nodes, and a node can belong to any number of multicast groups.
The first octet is
11111111) which is
the multicast address prefix. The second octet identifies the type of
multicast address, divided into flags (flgs) and scope (scop).
Permanent multicast addresses have the same meaning in every scope,
e.g. the group id
43h might be assigned to the "NTP
servers group". This means that
FF02::43 identifies all
NTP servers on the same link as the sender, whereas
FF0E::43 identifies all NTP servers on the Internet. It
is evident that multicast addresses of a local scope should be
preferred to global multicast addresses.
Transient multicast addresses have meaning only within a particular
scope, so two different sites can use the same address for different
purposes. The permanent multicast address with the same group ID as a
transient address also has no relationship to the transient
FF02::43 is distinct from
Multicast addresses must not be used as source addresses or appear in any routing headers. Using multicast addresses in this context would make error recovery impossible.
The multicast addresses with the group ID of zero, i.e.
FF0F::, are reserved and will never be assigned to any
multicast group. In addition to these, the following groups are
FF01::1 all node-local nodes
FF02::1 all link-local nodes
FF01::2 all node-local routers
FF02::2 all link-local routers
FF02::C all link-local IPv6 DHCP servers and relay agents
The neighbour discovery protocol uses solicited-node multicast
addresses. They are of the form
XXXX:XXXX is the lower 32 bits of the address. Selecting
the solicited-node address this way often reduces the amount of
multicast groups a node must join, as most of its uni- or anycast
addresses differ only in their prefixes. This is important as a node
must listen to the associated solicited-node addresses for every uni-
and anycast address it has.
[ADARCH] requires that every host recognize the following addresses as referring to itself:
In addition to these, a router must recognize the following addresses as identifying itself:
Street addresses have a clear topology. Everyone who ever has sent a letter has some kind of idea of how the letter is transported from A to B. For example, a letter from Oklahoma, USA to the (imaginary) address of
Mr John Smith
Mannerheimintie 345 A 67
FIN - 00300 HELSINKI
may be transported from the local post office to the Oklahoma central office from where it is flown to Europe, perhaps even straight to Finland. It would then be put with the mail going to Helsinki, and in Helsinki sent to the office of district 00300. Only there would the first two rows be significant; if there was no such address, or Mr Smith never lived there, the letter would be returned, else it would be delivered.
The designers of IPv6 have recognized the need to create topological addresses to make routing easier. The address space is so large that uncontrolled assignment of addresses soon would cause the routing tables to grow too big. [UAALL] presents an architecture for allocating IPv6 unicast addresses in a topologically reasonable manner. Even though the assignment of addresses is partly a policy matter, partly a question of routing, we briefly present the high level division of the addresses proposed.
The object of the unicast address assignment scheme is to create a hierarchy that greatly reduces the work needed to route packets over the Internet. This is achieved by allocating all addresses within a domain so that they have a common prefix. When two domains want to exchange routing information, they only need to pass the domain prefixes to each other. The routers can then be configured to route any packets with those prefixes to the other domain.
The Internet is expected to grow so large that even the "domain" of routing domains will grow too large to handle with a flat address model. It is therefore recommended that domains that are "close" in the physical topology of the Internet are given domain prefixes that themselves have a common prefix. How large the different parts of the prefixes need to be is dictated by the topology and size of the domains, and may vary in different parts of the Internet.
It is recommended that organizational and administrational boundaries should be ignored when assigning domain prefixes. Often the network topology does not reflect these boundaries, which means that assigning addresses according to them would lead to inefficient routing.
In the case of country boundaries the network connectivity seems to follow the country borders quite well. This should be reflected in the assignment of prefixes, but care should be taken as there may well be exceptions from this rule.
The stateless address autoconfiguration process is described in [ADCONF] and is closely related to the Neigbour Discovery protocol. The aim of stateless autoconfiguration is to make connecting machines to the network as easy as possible. In many cases it actually allows you to plug your machine into the network and start using it right away.
For autoconfiguration to work, an interface must be able to provide a unique identifier such as its link-layer address; in IEEE 802 networks the network address will be used. This identifier is then used to create a link-local IP address and all necessary multicast addresses for the node.
The tentative link-local IP address is announced in a Neighbour Solicitation message, which is repeated several times. If no Neighbour Advertisement message is received in response, the address is assigned to the interface. This does not actually verify that the address is unique, as the link may have been broken at the time of the Neighbour Solicitation. Later the Duplicate Address Detection protocol may be used if there is a suspicion that the address is not unique. Before the tentative address is assigned to the interface, the node may only send and receive Neighbour Solicitation and Advertisement messages.
The stateless autoconfiguration protocol is powerful enough to work in large networks with several routers, but larger sites may choose to use the stateful protocol to have more control over how the addresses are assigned. The stateful protocol is described in [DHCPv6] and is beyond the scope of this document.
Autoconfiguration also makes automatic renumbering of the nodes possible. Address prefixes and even addresses themselves have lifetimes that can be used to gracefully fade out old addresses and start using new ones instead. An address that is about to expire first becomes deprecated, which means that no new connections should be established using it, but that it still can be used on existing connections. Once an address expires, it must not be used at all.
The Neighbour Discovery protocol is used to discover local nodes, routers, link-layer addresses and to maintain reachability information based on them. It is described in [NDIP] in a form that assumes the link is broadcast capable. Links that do not support broadcast (e.g. as ATM) will have to extend the protocol to suit their needs.
The following functions are part of the Neighbour Discovery protocol.
To achieve its goals, the Neighbour Descovery protocol defines five packets. These are
The Neighbour Discovery protocol also includes support for a few
Inbound load on a node with several interfaces can be balanced by responding to solicitations with different link-layer addresses.
Anycast addresses can cause several responses to one solicitation, but the responses do not have the Override flag set. This allows the node to choose which of the link-layer addresses it will use.
Proxy nodes may respond with advertisements for nodes not present on the link, but that can be reached through the proxy. These advertisements do not have the override bit set, so if the actual node is present, it takes precedence. This is useful in mobility management.
[NDIP] describes the following conceptual model of a host. An implementation can, and probably will, differ from this model, but must perform the same functions.
|INCOMPLETE||Address resolution in progress.|
|REACHABLE||Has been reachable recently (in tens of seconds)|
|STALE||Not known to be reachable, but no attempt to determine its reachability should be made until traffic is sent to it.|
|DELAY||Give upper layer protocols some time to determine reachability before starting a probe.|
|PROBE|| Unicast Neighbour Solicitation probes are being sent.|
The Destination Cache is consulted, and if the address is not in it, a longest match is done on the Prefix list to determine if the address is link-local. Either way, the next-hop IP address is found, which is either link-local or the address of a router. The Destination Cache contains next-hop information to decrease the amount of next-hop determinations; even if next-hop determination is performed again, the cache entry does not need to be purged, as it can contain other link-layer parameters as well.
The Neighbour Cache is used to find the link-layer address of the destination. If the address is not in the cache Address Resolution is initiated in the INCOMPLETE state and the packet is queued for transmission when the address is resolved. The cache lookup may also result in Unicast Neighbour Solicitation, if the node has not been reachable lately.
When the destination is known to be REACHABLE, the packet can be transmitted.
Multicast addresses are always considered to be link-local, and a separate address resolution algorithm for each link type is required to find the link-local broadcast address to use.
The variables are set to the union of the values received in Router Advertisements. Variables that have only one possible setting are set according to the most recent advertisement. If an advertisement has some values set to "unspecified", the value of the variable must not be changed.
Router Solicitations can be sent when a node attaches to the link. The periodic Router Advertisements may be incomplete, but the response sent to a Router Solicitation is always compete. Before sending the first Router Solicitation, the node should delay for a short random time to avoid race conditions when several nodes are attached to the link simultaneously, for example after a power failure. If no response is received to the Router Solicitations, the node assumes that no routers are present, but will still listen for Router Advertisements in case a router appears on the network.
Address resolution is used to determine the link-layer address of a node whose IP address is on-link. The Neighbour Cache entry is set to INCOMPLETE and a Neighbour Solicitation message is sent to the solicited-node multicast address corresponding to the target IP address. The source link-layer address is sent with the Neighbour Solicitation, so that the response can be sent as unicast. Neighbour Solicitations are retransmitted until a response is received or the maximum limit is reached, which means that the address is unreachable.
When the solicited node receives a Neighbour Solicitation message, the Neighbour Cache entry for the sender is updated and set to the STALE state. This indicates that at least one-way transmission works, but that the return path is still untested. A Neighbour Advertisement with the Solicited flag set is then sent to the soliciting node.
Upon receipt of the Neighbour Advertisement with the Solicited bit set, the soliciting node sets its Neighbour Cache entry to REACHABLE. If the Solicited bit is not set, the message is not a response to the Neighbour Solicitation, and the entry is set to the STALE state.
The node that sent the Neighbour Solicitation knows that the path works both ways, whereas the solicited node only knows that it can receive messages. The solicited node can get knowledge of the return path from upper level protocols, or if that is not possible, by running the Neighbour Unreachability Detection algorithm.
These are the protocol constants used by a host (may wary depending on link type) [NDIP]
|Max. Solicitation Retry Delay||1 second|
|Solicitation Retry Interval||4 seconds|
|Max. Solicitation Retries||3 transmissions|
|Max. Multicast Solicitations||3 transmissions|
|Max. Unicast Solicitations||3 transmissions|
|Max. Anycast Delay||1 second|
|Max. Neighbour Advertisements||3 transmissions|
|Reachable Time||30,000 milliseconds|
|Retransmit Timer||1,000 milliseconds|
|First Probe Delay||5 seconds|
|Min. Random Factor||0.5|
|Max. Random Factor||1.5|
The IPv6 address assignment gives a host several addresses that it responds to. (see Required Addresses) Some hosts may need even more addresses, having several interfaces on different links. Sofar not much research has been done in this field, but several problems exist. Multihomed hosts must determine which interface to use for a transmission, much like routers do. This concept is carried even further in [MANYAD].
Bellovin proposes that IP addresses could be assigned to logical interfaces, so that a node would provide different services at different addresses. A public FTP service could have a well-known name and address, whereas a private service at the same host would use a different address. An even better example is the Archie service, which can be used remotely with an archie client or locally from a telnet prompt. The two services would have different names and addresses, thus eliminating the need to telnet to a certain port.
The ability to use different addresses for different services on the same host also has security implications. Currently a firewall needs to be able to block access to forbidden ports, and to allow connections to public ports. If the two were separate addresses, the only screening needed would be address based which is much more efficient.
It is even conceivable that every user on a host would be assigned an address of his own. This would increase the load on the host, but could provide many useful services. If an address would belong to a user, it could be used for accounting purposes, such as pay-by-use. User-level encryption would also be provided by the same mechanisms that provide host-level encryption without the need for another protocol.
The IPv6 address space along with the new any- and multicast addressing modes make the IPv6 Internet much more flexible than the old Internet. The protocol stack will be more complex, requiring a bit more processing power, but that is more than compensated for by the new features.
Configuring a host for the Internet has never been easy, so the autoconfiguration protocols are a welcome addition. Computer users are growing accustomed to "Plug-and-Play" devices and will appreciate that connecting to the Internet is equally easy. Network maintainers will find that their workload decreases markedly, as the number of misconfigured hosts drops drastically.
The Neighbour Discovery process along with Duplicate Address Detection and Unreachability Detection will probably make the new Internet more robust. Nodes react rapidly to changes in the network architecture and do not need to be reconfigured manually. Even larger renumbering operations that often are very error prone may be performed almost automatically and with better chances of success.
|Domain||A region with a common prefix, used in routing|
|Host||A computer on a network|
|Interface||Hardware connecting a host to a network|
|Internetwork||Several interconnected networks|
|IP address||A 128 bit number identifying one or several interfaces|
|Link layer||The low-level transmission media of a network|
|MTU||Maximum transmission unit, the largest packet that can be transmitted in one piece|
|Network||A group of computers connected to each other on some link|
|Node||Host or router|
|Prefix||Some number of the high-order bits of an address, usually written as NNNN/Y where NNNN is the prefix and Y is the number of bits|
|Router||Node providing the connection between two networks|
|Subnet||A logical part of a network with the same subnet prefix (netmask)|


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Simulation-driven Design Optimization And Modeling For Microwave Engineering
Slawomir Koziel, Xin-She Yang, Qi-Jun Zhang
Computer-aided full-wave electromagnetic (EM) analysis has been used in microwave engineering for the past decade. Initially, its main application area was design verification. Today, EM-simulation-driven optimization and design closure become increasingly important due to the complexity of microwave structures and increasing demands for accuracy. In many situations, theoretical models of microwave structures can only be used to yield the initial designs that need to be further fine-tuned to meet given performance requirements. In addition, EM-based design is a must for a growing number of microwave devices such as ultra-wideband (UWB) antennas, dielectric resonator antennas and substrate-integrated circuits. For circuits like these, no design-ready theoretical models are available, so design improvement can only be obtained through geometry adjustments based on repetitive, time-consuming simulations. On the other hand, various interactions between microwave devices and their environment, such as feeding structures and housing, must be taken into account, and this is only possible through full-wave EM analysis.
Electromagnetic simulations can be highly accurate, but they tend to be computationally expensive. Therefore, practical design optimization methods have to be computationally efficient, so that the number of CPU-intensive high-fidelity EM simulations is reduced as much as possible during the design process. For the same reasons, techniques for creating fast yet accurate models of microwave structures become crucially important.
In this edited book, the authors strive to review the state-of-the-art simulation-driven microwave design optimization and modeling. A group of international experts specialized in various aspects of microwave computer-aided design summarize and review a wide range of the latest developments and real-world applications. Topics include conventional and surrogate-based design optimization techniques, methods exploiting adjoint sensitivity, simulation-based tuning, space mapping, and several modeling methodologies, such as artificial neural networks and kriging. Applications and case studies include microwave filters, antennas, substrate integrated structures and various active components and circuits. The book also contains a few introductory chapters highlighting the fundamentals of optimization and modeling, gradient-based and derivative-free algorithms, metaheuristics, and surrogate-based optimization techniques, as well as finite difference and finite element methods.Contents:
- Introduction to Optimization and Gradient-Based Methods (Xin-She Yang and Slawomir Koziel)
- Derivative-Free Methods and Metaheuristics (Xin-She Yang and Slawomir Koziel)
- Surrogate-Based Optimization (Slawomir Koziel, Leifur Leifsson, and Xin-She Yang)
- Space Mapping (Slawomir Koziel, Stanislav Ogurtsov, Qingsha S Cheng, and John W Bandler)
- Tuning Space Mapping (Qingsha S Cheng, John W Bandler, and Slawomir Koziel)
- Robust Design Using Knowledge-Based Response Correction and Adaptive Design Specifications (Slawomir Koziel, Stanislav Ogurtsov, and Leifur Leifsson)
- Simulation-Driven Design of Broadband Antennas Using Surrogate-Based Optimization (Slawomir Koziel and Stanislav Ogurtsov)
- Neural Networks for Radio Frequency/Microwave Modeling (Chuan Zhang, Lei Zhang, and Qi-Jun Zhang)
- Parametric Modeling of Microwave Passive Components Using Combined Neural Network and Transfer Function (Yazi Cao, Venu-Madhav-Reddy Gongal-Reddy, and Qi-Jun Zhang)
- Parametric Sensitivity Macromodels for Gradient-Based Optimization (Krishnan Chemmangat, Francesco Ferranti, Tom Dhaene, and Luc Knockaert)
- Neural Space Mapping Methods for Electromagnetics-Based Yield Estimation (José E Rayas-Sánchez)
- Neural Network Inverse Modeling for Microwave Filter Design (Humayun Kabir, Ying Wang, Ming Yu, and Qi-Jun Zhang)
- Simulation-Driven Design of Microwave Filters for Space Applications (Elena Díaz Caballero, José Vicente Morro Ros, Héctor Esteban González, Vicente Enrique Bôria Esbert, Carmen Bachiller Martín, and Ángel Belenguer Martinez)
- Time Domain Adjoint Sensitivities: The Transmission Line Modeling (TLM) Case (Mohamed H Bakr and Osman S Ahmed)
- Boundary Conditions for Two-Dimensional Finite-Element Modeling of Microwave Devices (Tian-Hong Loh and Christos Mias)
- Boundary Conditions for Three-Dimensional Finite-Element Modeling of Microwave Devices (Tian-Hong Loh and Christos Mias)
Readership: Graduates, lecturers, and researchers in electrical engineering, as well as engineers who use numerical optimization in their design work. This book will be of great interest to researchers in the fields of microwave engineering, antenna design, and computational electromagnetics.


X-320M Web-Enabled Meteorological Station Controller
2 Digital IO,
6 Temperature / Humidity Sensor Inputs
1 Frequency Input
9-28VDC Power Supply not included
X-320M™ is a high-end, web enabled meteorological station controller. It can be combined with a variety of sensors from various manufacturers for remotely viewing current wind speed and direction, precipitation, temperature, humidity, solar radiation, barometric pressure, and more. Measured and calculated parameters are displayed beautifully on an easy to read web page that can be viewed anytime from a computer, tablet, or smartphone using a standard web-browser.
X-320M™ can send email/SMS notifications when monitored weather conditions exceed user specified set points.
X-320M™ can also remotely activate relays on other ControlByWeb™ products, which can be used to trigger an alarm or siren if, for example, the temperature or wind speed is too high or too low.
For a list of compatible meteorological sensors, click here.
- Intuitive Graphical User Interface.
- Compatible with a variety of meteorological sensors.
- Displays current data plus some historical data such as high and low temperatures and humidity, precipitation over time, wind gusts, and barometric pressure.*
- Calculates parameters such as heat index, wind chill, and dew point.*
- Dynamically creates rose diagram for wind direction.*
- Detailed site information.
- Password protected setup and status pages.
- Built-in logging capabilities.
- Control up to three remote relays.
- Send email alerts based on user defined conditions.
- Real-Time Clock with NTP server synchronization.
- Built-in web server.
- Remote services; X-320M can be configured to initiate a connection to a remote server.
- Field updatable.
- No software required.
- Rugged, DIN-Rail mount enclosure.
- Removable 14-Terminal connector.


Zenith is best known for the first practical wireless TV remote control, the Space Command, developed in 1956. A box advertising a remote control system often referred to as "Space Command Tuning". The Zenith remote, called the Space Command or Zenith Clicker, was an ultrasonic remote that used hammers hitting aluminium rods within the remote. So no batteries required! These rods rang at certain frequencies – forcing the TV to turn on or off, changing the channel or muting or un-muting the sound. The television interpreted the various tones as commands to switch the channel up or down, mute the sound, or turn itself on or off. The RC was an immediate hit, despite increasing the cost of compatible Zenith sets by a staggering 30 percent!
The original television remote control was a wired version, released in 1950, that soon attracted complaints about an unsightly length of cable from the viewer's chair to the television receiver. Eugene F. McDonald, Zenith President and founder, ordered his engineers to develop a wireless version, but the use of radio waves was soon discounted due to poor interference rejection inherent in 1950s radio receivers. Lead engineer Robert Adler then suggested that ultrasonic sound be used as a trigger mechanism. The buttons struck the rods with a nearly whisper-quiet sound (it earned the nickname 'The Clicker') but it ushered in the era of ultrasound remotes – a method used well into the 1980s.
The frequencies used in the Space Command remote were too high for the human ear to pick up, though they could be discernible to animals such as dogs and cats. There was a story going round at Zenith that during testing, one female lab assistant flinched every time the device was tested, due to her sharp sense of hearing.
The Zenith Space Command looked like a Star Trek prop, with just four protruding buttons – worlds away from today's devices which might crowd several dozen onto a slim rectangle of plastic.
The Space Command 600 was introduced in 1965 and this design was in use until the end of 1972. The 600 had an additional, distinctive feature, it could also adjust color hues.
The ultrasonic sound technology used in remote controles endured until the dawn of infrared in the 1980s.
Some models use the word Commander, for example the Space Commander 300.
What's your Zenith Space Command worth in 2021? Here are some recently sold items with prices.
|1985 Wood Grain Zenith SA1927W System 3||10/2021||$ 566.79|
|ZENITH SPACE COMMAND TELEVISION SET 19||07/2021||$ 340.07|
|Zenith Space Command SE2023W 20 Color TV||09/2021||$ 209.66|
|Zenith Space Command 19 Color TV Wood||08/2021||$ 192.70|
|Zenith Space Command 13 Color CRT TV||09/2021||$ 170.01|
|See all sold items on eBay for more prices||12/2021||-.--|


Two forgotten technology stocks are popping up today for pullbacks. Both were featured in last week’s earnings recap.
AT&T (T) gapped up last week after a surprisingly strong quarter. The telecom giant outperformed on both mobile and broadband subscribers. Now it may have an additional boost from 5G rollouts. T retraced the bullish gap and is holding near long-term lows. It also averages more than 150,000 options contracts per day.
Ericsson (ERIC) also surged last week, following its second consecutive strong quarter. The Swedish telecom supplier seems to have the double-impact of a long-term turnaround plus 5G demand. It’s been viewed as an alternate to Huawei.


The ISDT K4 charger is a Smart Dual channel Charger and runs both AC and DC input and has two separate channels to charge from. This charger's maximum charging power is 400W(AC) and 600W(DC) x2. The K4 has a strong performance, high-power dual-channel.
Main Features： 1.Support 1-8S lipo battery; 2.Dual channel Fast Charging; 3.AC/DC dual mode,AC output power 400W,DC output power600Wx2,meet the needs of different scenarios 4.Parallel Charging; 5.BattAir New Generation Interconnection Technology,identify battery type and gain battery setting by XT60 port conencting battery; 6.High-power dual-channel, the two channels are independent and do not interfere with each other. The maximum charging power of a single channel is up to 600W. A two-pronged approach, one step faster.
Specifications: Item Brand: ISTD Item Model: K4 Supported battery types: LiFe / Li-Ion / LiPo 1-8S, LiHv 1-7S, Pb 1-14S, MiMH 1-18s Max. charging power: AC 400W / DC 600W x2 Input voltage: AC 100~240V / DC 10~34V Balance current: 1.5A/Cell Max Charging current: 0.2-20A x2 Dimension: 182x177x55mm Output voltage: DC 1-34V Max. input current: 45A Weight: 1226g (2.7lb)
Package Includes 1x ISDT K4 Smart Dual Charger AC400W / DC600W 20W x2 1x AC Power Cable


Bandwidth Meter Pro provides users with detailed information regarding a lot of network parameters. It is a well-designed application that, in spite of the absence of an actual user-interface, will help network administrators to keep track of the bandwidth usage. Bandwidth Meter Pro supports monitoring all the popular network connections (wireless, LAN, ISDN, VPN, and many more.)
Bandwidth Meter Pro proves to be a reliable tool when it comes to measuring the bandwidth speed for various network types. It is also able to monitor multiple connections at the same time. It displays traffic data in a graphical manner and allows the user to customize the graphs that it provides.
Some may consider the lack of a graphical user-interface to be a drawback for Bandwidth Meter Pro, but as far as I’m concerned, the program includes a lot of useful tools that compensate that issue. The program runs silently in the system tray and will display network data only at user’s request. An important feature of Bandwidth Meter Pro is its ability to generate detailed daily, weekly, or monthly traffic reports. Also, the included stopwatch will help users monitor their connection for a specific period of time.
I consider Bandwidth Metter Pro to be a reliable solution for anyone who wants to know more about their network or Internet connections.


Proxy Workbench is a unique proxy server ideal for developers, trainers and security experts that displays its data in real-time. You can actually see the data flowing between your e-mail client and the e-mail server, web browser and web server or even analyse FTP in both Passive and Active modes. In addition, the 'pass through' protocol handler enables analysis of protocols where the server does not readily change.
The best feature is the animated connection diagram that graphically represents the history of each socket connection and allows you to drill into the finest of detail. This animation can even be exported to HTML and saved to the web!
- See data flow between socket connections
- Animated socket connection diagram
- 'Pass Through' protocol handler for debugging protocols
- Connection failure simulation strategies allow you to simulate:
a) Slow or asymmetric Internet connections (bandwidth throttling)
b) Servers that are underpowered, overloaded or under attack (connection refusal)
c) Intermittent connections (connection termination)
d) Disconnected network cables (connection dangling)
e) Data floods and droughts
- Natively handles HTTPS (secure sockets) and POP3
- Real time logging of data. All events are logged to a CSV format ready for advanced analysis with a database or spreadsheet.
- Animated system tray icon unobtrusively indicates data flow direction


No name is more closely associated with high-end audio amplifiers than that of Dan D’Agostino. During his career of more than 35 years, D’Agostino pioneered countless advances in the design of amplifiers, preamplifiers, CD players, and surround-sound processors. He is known as the audio industry’s most passionate promoter of high-quality, high-powered amplification. Makers of the world’s finest loudspeakers rely on D’Agostino-designed amplifiers for their most important demonstrations.
Dan D’Agostino was founder and chief engineer of Krell Industries through 2009. Since the inception of DDMAS in 2011, energized with a new organization and new state-of-the-art designs, the products that bear his name not only achieve new levels of sound quality, they also look like nothing else in the industry. The new designs combine an elegant aesthetic flair coupled to inventive circuit topologies and innovative materials.
Starting with the Momentum Mono amplifier, the D’Agostino product line now extends upwards to the awe inspiring Relentless Mono amplifier and outwards to the new Progression Integrated amplifier. The Relentless Mono Amplifier is an all-out assault on the amplifier category. Capable of driving any speaker to its fullest capability, the extraordinary power output of the Relentless Mono is only matched by its sublime low volume sound quality. The Progression Integrated amplifier connects the high-performance core of D’Agostino products to the exciting world of streaming audio with Tidal, Quobuz, and Spotify services as standard offerings.
As impressive as these designs may sound on paper, the only way you can truly appreciate their warmth, detail and unmatched beauty is to experience them at your nearest Dan D’Agostino Master Audio Systems dealer.
Combining engrossing sound quality, a flexible platform, and striking aesthetics, the Relentless Preamplifier is the ultimate centerpiece for a truly brilliant audio system.
Created for uncompromising listeners and needing three chassis to execute, the Relentless Preamplifier elevates every aspect of preamplifier design. Individual audio chassis and power sections ensure complete isolation from noise. Audio and power signals are carried through interlocking feet shortening signal feeds to the absolute minimum.
The standard model can be augmented with a plug-in digital streaming module including legacy digital inputs, network, and internet music streaming. Tidal, Qobuz, Spotify, and Roon are all directly supported. An iOS app makes for easy, intuitive operation.
The new Relentless Preamplifier is the ultimate in preamplifier design. The preamplifier plays a critical role in musical playback; the point in the reproduction stage when the music signal is particularly susceptible to compromise through noise and distortion. The use of three separate chassis in the design of the Relentless Preamplifier—a dedicated audio chassis for each channel separated by a power supply/control section—addresses these challenges and brings other benefits as well.
Positioned between the two audio channels, the power supply makes use of extensive electrical and magnetic shielding to keep radiated interference out of critical preamplifier circuits. Internal line conditioning circuitry filters RF noise on the AC power and compensates for asymmetric power waveforms and DC on the mains. Power for the preamplifier stages comes from two 150 VA toroidal transformers – one dedicated to the analog circuitry and one for the digital and control circuitry. These transformers drive an 8-amp bridge rectifier and 26,400 microfarads of filter capacitance. The two regulators for the analog stages are scaled-down versions of those used in the Relentless Mono amplifier. The separate digital regulator is a monolithic platform with thermal and current limiting protection in the unlikely event of a fault. The Relentless Preamplifier has nearly as much power supply capability as many power amplifiers.
The input stage in each mono preamplifier is the result of a design experiment for a circuit that hadn’t been used in any previous D’Agostino preamplifier. As part of development, a version was tested in the existing Momentum Preamplifier. The overwhelmingly positive results led directly to the launch of the Momentum HD Preamplifier. From there, the fullest expression of this idea was developed, and the Relentless Preamplifier was underway.
The audio circuit topology starts with a new discrete differential FET input stage featuring a voltage input signal capability of an extraordinary 30 volts. With an input impedance of over 1 M Ohm, the Relentless Preamplifier’s front end is immune to source related electrical issues. In normal operation, component heating can lead to performance and sonic degradation. Developed specifically for the Relentless Preamplifier, a unique circuit maintains a stable bias so that temperature related anomalies are offset thus preserving performance during extended listening.
Featuring only balanced XLR inputs the Relentless Preamplifier topology rejects common-mode input noise over an unusually wide bandwidth. All signal gain is realized in the current domain using proprietary multiple-output current mirrors with nearly 30 times the linearity of other designs. Executed with four-layer circuit boards for superior signal quality. The use of four-layer boards dramatically reduces distortion and propagation levels as compared to the more commonplace, two layer boards.
The analog and digital circuit elements are isolated, including ground planes, from each other. Where necessary, digital control signals are optically coupled to analog circuits. The signal switching relays are hermetically sealed and use gold-plated contacts for maximum signal integrity.
Utilizing no negative feedback anywhere, core D’Agostino circuit concepts include a signal path that is fully complementary and balanced from input to output achieving a frequency response flat to 120 kHz.. The overall result is a musically dense and dynamically rich signal presented to the balanced outputs.
Arguably, the most striking element of the Relentless Preamplifier is the pair of volume controls fronting the two audio chassis. Volume control circuits are often overlooked, if not actively minimized, in preamplifier designs. This is not the case in the Relentless Preamplifier. Each volume control is constructed using 14 separate metal components ensuring the smoothest response and control of the military-grade, high-linearity solid-state switches and discrete precision resistors employed in the volume circuit. The bandwidth and transient response of the Relentless Preamplifier is completely unaffected by the volume setting. As a result, high frequencies sound especially smooth and extended, and music emerges from “jet black” silence.
The volume settings are displayed via the elegant swiss watch inspired volume wands or can be displayed numerically, from 0 to 99.
The Relentless Preamplifier is a two source/two zone preamplifier. This means that the Relentless Preamplifier can simultaneously control the switching and volume of two sources in two separate rooms or zones. Listening sources may be two analog sources or when equipped with the optional digital streaming module, one digital source and one analog source. In a one zone system, either volume control will adjust volume in the main room or Zone 1. If two zone operation is desired, the upper volume control manages the Zone 1 volume and the lower volume control adjusts the Zone 2 volume.
Housed in machined aluminum and copper, the Relentless Preamplifier remote control is a comfortable design operated via touch pad. Control buttons are minimized with most of the operation executed by navigating via a tactile touch pad. Bluetooth 5.0 technology extends the usable range of the remote control and eliminates the line-of-sight issues that plague conventional infrared designs. New for the Relentless Preamplifier is bi-directional remote-control functionality. All adjustments made on the Relentless Preamplifier front panel are reflected on the remote control’s display screen including input, volume, and balance selections.


Bland is a platform for AI phone calling. Using our API, you can easily send or receive phone calls with a programmable voice agent.
We really care about making our phone calls…
- Fast: sub-second latency from person speaking to AI responding.
- Reliable: it’s our responsibility, day in and day out, to make sure your phone calls work. No exceptions.
- Ultra flexible: configure all aspects of your agent’s behavior, by settings it’s voice, creating transfer scenarios, configuring the initial greeting, etc.
What you can do with Bland
Send phone calls
Dispatch AI phone calls to call customers, leads, and to streamline operations.
Set up inbound numbers
Create inbound phone numbers for customer support, etc.
Do live function calling
Connect external APIs and take live actions during phone calls.
Extract structured data from calls
Extract JSON data to answer questions about your calls.
Create call campaigns
Simultaneously send thousands of calls at once.
Fine-tune a custom LLM
Fine-tune a custom LLM using your enterprise’ call recordings and transcripts.


Often the forgotten component of any network design, your computer network cabling infrastructure can become your biggest headache. Designing and planning a structured cable plant design for your building or office simplifies management of moves, adds and changes, which comprise a majority of your day-to-day administration headaches and provides you with a reliable infrastructure for data transport. Having designed and implemented systems for clients throughout Michigan, our expertise will help you in implementing a "transparent", structured cabling system that allows you to concentrate on more important issues, such as running your network.
ITS designs, installs, and maintains structured voice, data (computer network cabling, ie: Ethernet) and fiber-optic cabling systems (single and multi-mode fiber optic) based upon the specific needs of your company or business. Our structured cabling system designs:
Allow for adds, moves, and changes (MACs) quickly and easily.
Allow growth with minimal incremental cost.
Accommodate a wide variety of hardware configurations and network topologies
Integrate with any computer and telephone system to allow for maximum interchangeability and flexibility.
Utilize high-quality, industry-leading components with stringent manufacturer warranties.
Are guaranteed to be certified to industry-standard specifications, such as TIA/EIA-568-B Commercial Building Telecommunications Cabling Standard.
Pride in workmanship still counts! Installation services include implementation of any cabling design and our maintenance service extends to providing support for any of our installations as well as non-ITS installations. Considering that a typical Ethernet infrastructure will be in place for 20-30 years, and that critical technologies such as voice/telephone (VoIP), and video surveillance (IP-based video), that have traditionally been installed on separate copper and coaxial networks are now becoming part of the LAN network infrastructure, we feel that it's more critical than it ever has been to select the right infrastructure partner from the start.
One of the biggest advantages of working with ITS on your next voice or data cabling or fiber project is that we are a one-stop solution, our expertise doesn't end at the wall jack. Once we have completed your cabling or fiber project, we won't leave you hanging when you ask us about power, cooling, networking or telephony issues. Why? Because we are experts in the design, integration, installation and support of highly scalable power and cooling solutions. What this all means to you is that this consolidated training and expertise allows us to bring a complete solution to the table because we understand the data center from the copper and fiber, to the metals, racks and cable raceway, to the power and cooling needs, to the final integration with your voice and data systems, wireless infrastructure and VoIP systems. We strive to provide our customers with comprehensive solutions. And that doesn't mean that you have to be huge to call us, we're happy to work on small projects for customers only needing a drop or two, all the way up to multi-story, multi-faceted datacenters. Every customer is important and appreciated here!
Testing and Certification
Many people "install" network cabling, but fail to actually test and certify it. There is a difference. Simply installing cabling and then running a "tester" on it is not the same as certifying that the voice and data cabling will actually meet the rated speed that you're paying for. Devices may light up at both ends of the connection, but how do you really know that you're getting 100Mb, and maybe not 10Mb? When network problems arise, do you really want to have to worry about the wiring being suspect?
ITS Testing and Certification Reports because of the demanding requirements of today's network infrastructure, the only true way to confirm that your cable infrastructure actually meets the specifications and quality level that you've purchased is to test and certify it. We test and certify all twisted-pair cabling for Category 5/5e/6 compliance (where applicable), including continuity, proper polarity, crossed-pairs, NEXT, and shorts with an industry-standard Fluke DTX Level IV cable certifier, or equivalent. We also test and certify all our fiber optic cabling installations. Once ITS completes an infrastructure installation, you can be assured that your physical infrastructure meets the specs that you paid for. We also maintain an archive copy of your cable/fiber scans on site, so that they can be provided in the future if you've lost your copy.
Our voice and data cabling technicians are certified too. We do not hire the lowest cost personnel that we can find or subcontract our work out to someone else. We look for high quality, professional, trained and certified full-time employees, and then continue to train them to stay abreast of the latest industry standards and performance requirements from BICSI, EIA/TIA, CompTIA, etc. We take great pride in the high quality of the workmanship that we provide and we back it up with a Lifetime Workmanship Warranty.
Graphically Document Network and Cabling Systems
Network and cabling system documentation is generated graphically using Microsoft Visio or AutoCAD. We can produce professional full color illustrations and documentation. These services include logical network design, cable routing, punch block layout, and patch panel systems for any network. This is in addition to our cable and fiber optic certification scan reports which are provided upon completion of every job.
High Quality Materials
Our infrastructure solutions primarily use industry-leading Panduit and General Cable solutions, which, when installed together, provide the customer with a 25-year product warranty. However, we have installed most major vendors products and can accommodate any specific vendor requests, including, but not limited to: Panduit, AllenTel, AT&T/Lucent, Belden, Berk-Tek, Cablofil, Chatsworth, General Cable, Hubbell, Krone, Leviton, Mohawk/CDT, Nordx/CDT, Ortronics, Siemon and Wiremold.
ITS stands behind our work with a unique Lifetime Warranty, which states that we warrant the workmanship of our computer cabling for the lifetime of its installation. Materials are warranted for one (1) year, or the duration of the manufacturer's warranty whichever is longer.
Computer Room & Data Center Design
ITS has the design expertise to develop programming information and specifications for Computer Rooms, Data Centers, Telecommunications Rooms, and Equipment Closets.
We can provide the following services: Inventory and documentation of existing client equipment. Documentation of existing voice and data circuits and facilities. Coordination with equipment vendors. Space planning and design development for new equipment rooms. Comprehensive specifications for raised floors and overhead cable management. Complete equipment matrix detailing power, HVAC, loading, and space requirements. Visio/CAD drawings showing layout of equipment rooms, and equipment racks. Design of in-room fiber and copper cabling for complete equipment connectivity.
Categories of Copper Cabling
Customers often ask what the differences are between the various types of cable (ie: Cat3, Cat5, etc.). In a nutshell, the higher the number, the better the performance, and accordingly, the higher the price tag. The most common types of cabling are Category 3 (used primarily for voice today), Category 5E (the most common type of cabling, used for both voice and data, and also supports Gigabit Ethernet), and Category 6. Customers sometimes request Category 6 because they think it's a requirement for Gigabit Ethernet, which isn't quite correct. Gigabit Ethernet can run on Category 5 cabling, however, Category 6 will perform better. The key is the bandwidth the cable supports.
Category 6 is rated at 250Mhz (and the newest Category 6a specifies 500Mhz), whereas Category 5E is rated at 100Mhz. The higher megahertz support allows cabling to handle the greater amount of noise and crosstalk that occurs on a wire when faster (ie: gigabit and 10G) connections are running on that wire. When signals are run at a higher frequency that the cabling is not rated for, it can cause errors and anomalies.
So what are the cost variances? Generally speaking, you can expect to pay a 20% price premium between Cat6 and Cat5E, and a 50% price premium between Cat 5E and Cat 6a.


- RE500X comes equipped with the latest wireless technology, Wi-Fi 6, for faster speeds, greater capacity, and reduced network congestion.
- Creates a Mesh network by connecting to a OneMesh router for seamless whole-home coverage.
- Gigabit Ethernet Port – Provides faster-wired connections to smart TVs, computers and gaming consoles
- Intelligent Signal Light – Helps to determine the best location for optimal Wi-Fi coverage by indicating the signal strength in the current placement
- AP Mode – Creates a new Wi-Fi access point to enhance your wired network with Wi-Fi capability
- TP-LINK Tether App – Easily access and manage your network using any iOS or Android mobile device
- Ultimate Compatibility – Extends the range of any Wi-Fi router or wireless access point
This extender works better than any I have tried, and that's quite a few. I liked it so much I bought the WIFI 6 AX3000 router and connected them and now my whole house is covered with strong wifi. And at a much better price than those mesh units.
Easy and effective
Easy to install. Highly effective.
Does what it says and super easy to setup
Adjusts for different locations in the house.
This product did exactly what I needed. My other Linksys extender had trouble working in relative proximity to our primary wifi router. This product had no such difficulties and so far has been rock solid.
Good product would buy again
It's a little bulky as far as size but the signal on my mesh network it great