Sending text messages on the ISM band vs the law - Page 1
Forum section: electronics / rf-microwave

author: MichalPL
author_rank: Contributor
timestamp: July 21, 2018, 06:51:11 pm
content: Hi, I'm thinking of creating a toy that would utilize the ISM band to send text messages. Point-to-point or point-to-multipoint, but without utilizing the cellular network, just ISM band transmission.I wonder if there are any laws that make it forbidden or call for some special license in a given country.I believe the answer is not that obvious. Of course many devices communicate with each other via open text messages sent over RF in the ISM band, and that's what this band is for, but there's a difference between a remote control asking the gate to "open up" and one user sending a text message to another one. I worry that it might be interpreted as creation of some telecommunication device that falls under some special laws/regulations.I'm especially interested in the USA, Canadian, and European markets. Please let me know if you have any knowledge in this area.Another question that arises is encyption. Since this will be just a toy, I believe the messages can be sent via open text. But let's assume I decide to encrypt them.Again, encryption in sending control signals is ubiquituous, however encrypted text messages sent between users may be a different thing. A matter of national security, etc. ;-) And yes, I know, that cell phones do encrypt transmission as well, but they may fall under some specials laws, as telecommunication devices.And isn't encryption forbidden e.g. in France, by the way?Could you help me sort this out?

author: helius
author_rank: Super Contributor
timestamp: July 21, 2018, 07:27:47 pm
content: Quote from: MichalPL on July 21, 2018, 06:51:11 pmThe ISM bands are for "Industrial, Scientific, and Medical" purposes. The common factor is that they arenon-communicationapplications which would be expected by their nature to cause RF interference over a wide band. Communication devices in the ISM bands require regulatory approval, which depends on them using spread-spectrum techniques to increase their immunity to interference and minimize interference with other devices.In the US, the FCC regulates communication equipment using the ISM bands through Part 15. In Europe, the SRD regulations apply.

author: RoGeorge
author_rank: Super Contributor
timestamp: July 21, 2018, 07:32:18 pm
content: Short answer is 'no'.It wouldn't be legal.

author: MichalPL
author_rank: Contributor
timestamp: July 21, 2018, 07:38:32 pm
content: Quote from: helius on July 21, 2018, 07:27:47 pmWell, that's where the name comes from, yet in Europe this means 433 MHz, 868 MHz and 2.4 GHz and you can find tons of wireless doorbells, home alarms, weather stations and similar devices using these band, none of which could be classified as industrial, scientific, or medical. So the name shouldn't be treated literally, I believe.

author: MichalPL
author_rank: Contributor
timestamp: July 21, 2018, 07:44:44 pm
content: Quote from: RoGeorge on July 21, 2018, 07:32:18 pmThank you, RoGeorge, but could you elaborate on it a bit?While looking at the Polish laws for various frequencies from the ISM band, one can find annotations stating that 'this freqency band cannot be used for transmission of audio or voice', and similar, however none of them mentions text messages.

author: tsman
author_rank: Frequent Contributor
timestamp: July 21, 2018, 07:46:01 pm
content: It has been done before so presumably you're okay in the US at least. The long discontinued Girltech IM ME and Cybiko were toys that did this. The IM ME was designed purely for text messaging and had a USB RF dongle for your PC as well to act as a gateway. The Cybiko had text messaging + basic gaming and you could dedicate a handset as a gateway. Otherwise both would just send messages directly to a nearby device. My memory is hazy on the details as this was years ago now.The IM ME was only for the US market AFAIK. The Cybiko supposedly was sold in Europe as well on a different frequency range. No encryption on either of them.

author: MichalPL
author_rank: Contributor
timestamp: July 21, 2018, 07:48:42 pm
content: Besides, let's consider such a simple thought experiment:It would be legal to use the ISM band to remotely control a lightbulb, right?Or a LED indicator.Pressing A key on the remote control would send "A" message over the air, which would be interpreted by the receiver as an instruction to turn on the 'A' indicator LED. Same for B, C, etc.That's legal, right?So what would make it illegal to display 'A' on the LCD screen instead of lighting up the 'A' LED in response to receiving the 'A' message over RF?

author: MichalPL
author_rank: Contributor
timestamp: July 21, 2018, 07:51:58 pm
content: Quote from: tsman on July 21, 2018, 07:46:01 pmThank you, tsman. That's why I need references to specific acts of law that would state that it's illegal. Because it's too easy (and painful) to dump a project just because wethinkitmaybe illegal.

author: nali
author_rank: Frequent Contributor
timestamp: July 21, 2018, 07:56:15 pm
content: Well this is from Ofcom (UK):Quote..the last few words being pertinent

author: tsman
author_rank: Frequent Contributor
timestamp: July 21, 2018, 08:03:15 pm
content: It looks like the Cybiko Xtreme was officially sold in the UK at one point. There are brief mentions of people buying them and also how the UK model had the same ROM as the US model.

author: MichalPL
author_rank: Contributor
timestamp: July 21, 2018, 08:06:03 pm
content: Take a look at page 48 of this Cybiko manual:ftp://ftp.navigator.co.uk/pub/cybiko/xtreme%20cd%20-%20most%20files%20work%20with%20classic%20too/docs/online_guide.pdfLooks like it was approved by a notified body.So, I guess, the question is, what's the official definition of a 'applications in the field of telecommunications'

author: tsman
author_rank: Frequent Contributor
timestamp: July 21, 2018, 08:06:44 pm
content: Quote from: nali on July 21, 2018, 07:56:15 pmIt depends on the transmit power. If it falls under the classification as a Short Range Device then you should be okay to do this.https://www.ofcom.org.uk/__data/assets/pdf_file/0028/84970/ir-2030-july-2017.pdfQuote

author: MichalPL
author_rank: Contributor
timestamp: July 21, 2018, 08:25:29 pm
content: Thank you, tsman. So now the remaining issues/questions are:1) Are these UK regulations valid for the whole of EU, or do some member states make exceptions to this rule?2) What about the 915 MHz band in the USA?3) What about encryption?

author: tsman
author_rank: Frequent Contributor
timestamp: July 21, 2018, 08:48:09 pm
content: Quote from: MichalPL on July 21, 2018, 08:25:29 pmYou'll need to dig around inhttps://www.cept.org/ecc/topics/srd-regulations-and-indicative-list-of-equipment-sub-classesand readERC/REC 70-03which tells you who has implemented what for each frequency range. You'll probably want to use 868MHz for Europe but you'll need to pay attention to e.r.p, duty cycle and modulation to see what is allowed.Quote from: MichalPL on July 21, 2018, 08:25:29 pmThe FCC database lists the IM ME as using908.45-920.6 MHzand the US model Cybiko as using903.2-926.8 MHz.Quote from: MichalPL on July 21, 2018, 08:25:29 pmMy guess is that it is okay since you can buy 868MHz RF datalink and LoRa modules that don't have restrictions on usage or encryption. Have fun digging around in the docs though to confirm this.

author: rhb
author_rank: Super Contributor
timestamp: July 22, 2018, 12:17:15 am
content: For the USA read the FCC Part 15 regulations. Except for bands used for radionavigation, you can do anything you want so long as the power levels do not exceed the limits set.I am interested in developing long range point to point data communications within those limits. A rough goal is 2 KB/day over 3000 miles reliably, but I've not done the detailed mathematical analyses. It's a fairly complex problem.Communication from Great Britain to Australia has been demonstrated using the WSPR protocol at 150 mW.https://shop.languagespy.com/blogs/news/113037253-uk-to-australia-with-a-pi-tx

author: rhb
author_rank: Super Contributor
timestamp: July 22, 2018, 01:46:44 am
content: Quote from: blueskull on July 22, 2018, 12:38:56 amPeople who made trick concealed compartments in cars and trucks have received 20 year prison sentences because they made one which was used by a drug smuggler.WiFi is legal and encrypted. So it's all about use case.I'd be interested to know of any* country which permits encrypted messages on the HAM bands.In theory, if you use direct sequence spread spectrum at low enough power levels with a truly random key your signal cannot be detected as a wireless transmission. I can't say I know what the limitations are and I've considered the mathematics of that a great deal for a long time.

author: helius
author_rank: Super Contributor
timestamp: July 22, 2018, 01:57:31 am
content: It's worth pointing out that although ISM band devices areunlicensed, they are notunregulated. Theuserof a (e.g. 2.4 GHz) device does not require alicense. The manufacturer of the devicedoesrequire agencyapprovalto produce and market the device.HAM bands are under a different system of rules. HAM operators arelicensed. The license provides some privileges that do not normally apply, such as the right to construct and use radio equipment without agencyapproval. The catch is that the operator must identify themselves using their callsign and follow the rules around noncommercial, nonencrypted communication.

author: james_s
author_rank: Super Contributor
timestamp: July 29, 2018, 11:15:18 pm
content: WiFi operates in the ISM band, if it were illegal to send text that way then what happens if you send an email or instant message from your laptop? Send an iMessage from your iPhone whilst it's connected to WiFi? I don't think there's likely to be any legal issues here provided the power limits are observed.

author: Lord of nothing
author_rank: Super Contributor
timestamp: July 30, 2018, 03:22:09 pm
content: sry I dont read all.Quoteit is!You can use or Build an CB Radio with and Build in Sound Modem and Transmit with any Sound Modem Think you want. Here in Europe Legal.Jamming the Channel 25 with 12W legal and nobody can do anything against.How about a Digital PMR446 Radio System?https://www.hytera-mobilfunk.com/de/produkt/details/hytera-pd365lf-dmr-tier-i/With a DMR Radio you can Transmitt Text. If you want Transmitt also Voice you can buy legally the Chipset from:http://www.dvsinc.com/

author: CJay
author_rank: Super Contributor
timestamp: July 30, 2018, 03:33:35 pm
content: Quote from: tsman on July 21, 2018, 08:03:15 pmCybiko was definitely sold in the UK, I had a dozen of them when they were sold off for a quid or two each.

author: vk6hdx
author_rank: Regular Contributor
timestamp: August 01, 2018, 01:09:13 pm
content: Doesn't WiFi /Zigbee / etc, use the ISM bands? Couldn't your product use something like an ESP8266 to send the messages? I'm not sure if i'm missing something but can't see what the regulatory issues would be provided whatever module you use is approved?