RS-232 HP 8595E Spectrum Analyzer DB-25 pinout - Page 1
Forum section: electronics / testgear

author: candrian
author_rank: Regular Contributor
timestamp: February 25, 2023, 07:16:36 pm
content: Hi all,I own the HP 8595E which comes with 023 option (RS232). What I'm trying to, with no success yet, is to connect the HP with my PC to control it remotely.I'm using a USB to RS232 adapter which is functional, confirmed by jumping RX/TX signals but i can't receive any replies from the SA while i can probe the commands I send on the SA DB-25 connector. The wiring on DB-25 connector is custom made. The RS232 configuration (baud rate etc) has been cross checked and is similar on both SA and RealTerm.The commands i have tried with no results areID;IP;*IDN?The strange thing now comes on DB-25 connector pinout. The HP 8590 Series Spectrum Analyzer Programmer's Guidehttps://www.keysight.com/us/en/assets/9018-01030/user-manuals/9018-01030.pdfgives the following pin out. Page 720 where the option it refers to is 043 which is different from 023 I have but both are RS232. I don't know if that makes any changes to the connector pinout but I couldn't find any relative info regarding option 023.1. DCD Measured 0V2. RxD Measured -11V3. TxD Measured 0V4. DTR Measured +11V5. GND Measured 0V6. DSR Measured 0V7. RTS Measured 0V8. CTS Measured 0V9. RI Measured 0VWhile the universal DB-25 pinout is1. Shield Ground2. TxD3. RxD4. RTS5. CTS6. DSR7. GND8. DCD20. DTRFrom the above measurements (reference the connector chassis) I may assume that the SA TxD is Pin 2 and RxD Pin 3 while the GND pin is still not clear which one is. Is it pin 5 or pin 7?There is also a note "The spectrum analyzer checks its CTS input before transmitting data to the computer. If the CTS line is false, the spectrum analyzer will not transmit data. The spectrum analyzer transmits data when the CTS line is true"So I tried1. Connecting my PC USB-RS232 adapter TxD to pin 3 of SA DB-25, RxD to pin 2 and ground on pin 5. No results2. Connecting my PC USB-RS232 adapter RxD to pin 3 of SA DB-25, TxD to pin 2 and ground on pin 5. No results3. Connecting my PC USB-RS232 adapter TxD to pin 3 of SA DB-25, RxD to pin 2 and ground on pin 7. No results4. Connecting my PC USB-RS232 adapter TxD to pin 3 of SA DB-25, RxD to pin 2 and ground on pin 7 and set CTS pin 8 to -6V using an external power supply in order to set it True. No results5. I also tried connecting 8 CTS, 7 RTS and 1 DCD together but nothing changed in the communication.6. I also tried different combinations of the above that i didn't note down.Does anybody have the confirmed pinout of the DB-25 RS232 connector of SA 8595E?

author: Emo
author_rank: Regular Contributor
timestamp: February 25, 2023, 07:33:53 pm
content: Hi Candrian,Besides the correct pinout you also need to check for baudrate and/or parity/stop bitsA safe guess for these old instruments is 9600 baud 8N1Eric

author: candrian
author_rank: Regular Contributor
timestamp: February 25, 2023, 08:47:13 pm
content: I just teardown the instrument and removed the RS232 board so to confirm the pinout.P1. GND ( It should be the shielding but it's shorted to GND)P2. is MC1488 Output so it should be the TxDP3. is SN75189 Input so it should be the RxDP4. is MC1488 Output so if we follow the universal pinout it may be RTSP5. is SN75189 Input so if we follow the universal pinout it may be CTSP6. unconnectedP7. GNDP8. is SN75189 Input so if we follow the universal pinout it may be DCDP20. is MC1488 Output so if we follow the universal pinout it may be DTRSo following the Programmer's Guide I made the following connections and i gave it a trySA PC (USB RS232 adapter)P1. GND UnconnectedP2. TxD RxDP3. RxD TxDP4. RTS DCDP5. CTS DTR (measured -6V coming from the adapter)P6. unconnectedP7. GND GNDP8. DCD RTSP20. DTR CTSPS. SA is operating RS232 at -11V to +11V while my adapter is operating at -6V to +6V but this shouldn't be the case.But still I don't receive any replies.SA Baud rate is 9600, my RealTerm config is Parity None, Data bits 8, Stop bit 1, No hardware flow control

author: candrian
author_rank: Regular Contributor
timestamp: September 27, 2024, 07:30:21 pm
content: I'm coming back to my original post after a while.It looks like option 23 RS232 that my Spectrum Analyzer came with isn't the correct interface to be used for remote control. The supported commands looks to be for a different use but not remote control. Maybe for a connection to a printer/plotter. After looking on the internet I found out that the 8595E with serial numbers starting with prefixes <3525U (as mine) have a single port instead of two! This is something I found completely by accident!It sounds very strange to me, models with same part number to use different configuration boards. According to Keysight though, both kits / part numbers can be used for both editions but as I can suppose you should drill the holes on the back aluminum plate on your own for the second port to be mounted. That's why they recommend if you choose to go with the dual port when you already have a single port, to perform the installation in an Official Keysight service center. As I can imagine they will also replace the back aluminum plate with a new one.https://docs.keysight.com/kkbopen/what-are-the-hardware-details-regarding-the-single-i-o-rs-232-gpib-parallel-interface-versus-the-dual-i-o-configurations-for-the-8590-series-588265631.htmlIs there a chance any of you to have any of the following for sale?5062-6454or08590-60380

author: rcjoy
author_rank: Regular Contributor
timestamp: September 27, 2024, 11:04:54 pm
content: When sending commands to the analyzer, are you sure you terminated each one with a semicolon?It seems it should work with what you already have; the dual port option just adds a printer parallel port.

author: candrian
author_rank: Regular Contributor
timestamp: September 28, 2024, 07:49:40 pm
content: Well, if I click the copy button I can see raw data coming from the serial port. The same when I click CONFIG -> 1 of more -> 2 of more -> 3 of more -> Print config -> PRINTER SETUP , I get 0x1B 0x45.But when I try to send IP; I don't get anything back.

author: rcjoy
author_rank: Regular Contributor
timestamp: September 29, 2024, 01:11:44 am
content: The "IP;" command is not a query, so you will not get anything back from the instrument. However you should see the instrument change it's settings back to the preset state.Try "ID?;" to get the instrument identification; that will return text.

author: candrian
author_rank: Regular Contributor
timestamp: September 29, 2024, 11:05:05 am
content: I have already tried "ID?;" but it didn't work. In order to receive data from the SA I set DTR from PC side which is connected to CTS of SA. If this pin is not set SA doesn't send any data.According to datasheetThe spectrum analyzer checks its CTS input before transmitting data to the computer. If theCTS line is false, the spectrum analyzer will not transmit data. The spectrum analyzer transmitsdata when the CTS line is true.The spectrum analyzer sets the DTR line (PC CTS) false when its input buffer is fullI didn't find any relative combination of control signals for sending data to SA. Do you know if something exists but I'm not aware of?

author: rcjoy
author_rank: Regular Contributor
timestamp: September 29, 2024, 12:34:38 pm
content: In an earlier post you mentioned that on the PC side your "RealTerm config" was "no hardware flow control". If the SA is using hardware flow control, try having your PC also use hardware flow control.Also make sure your cable is wired correctly, as shown in Appenix C of the 8590 Programmer's Gude. That manual shows Option 043 with the 9-pin connector on the SA, so just translate the pin numbers to your 25-pin connector on Option 023.Note the simpler wiring of figure C-4 & C-5 if the PC side is not using any flow control.

author: candrian
author_rank: Regular Contributor
timestamp: November 25, 2024, 06:09:44 pm
content: It has been a while but I had some time in the weekend and I worked on this issue. It seems I found what was set wrong. I'm replying mostly to help any others that may come across the same issue.According to the Programmer's Guide document:Spectrum Analyzer RS232 signals:DCD: If true SA will receive data. If false SA will drop data. (It sound to me very suspicious!)CTS: If true SA will transmit data.I was able to receive data through RS232 when pushing the copy button but I wasn't able to send any commands. At least I didn't get any response to the display of the SA neither to the RS232.So I measured DCD on the SA side connector and I saw that it was zero volt. I hooked it up to CTS which I was able to control ( set true/false ) through realterm and by the time I set it True I was able to control the SA through the RS232! Now I'm able to send commands through RS232.The connection that worked for me (option 023 25pin RS232 connector):SA (25pin) PC RS232 adapter to USB1. GND N/C2. TxD >----> RxD3. RxD <----< TxD4. RTS >----> DCD ( I didn't confirm if the RS232 adapter I use controls this pin)5. CTS <----< DTR (Important for a successful communication. Must be Set true)6. N/C7. GND ------- GND8. DCD <----< DTR (Important for a successful communication. Must be Set true)20. DTR >------ CTS ( I didn't confirm if the RS232 adapter I use controls this pin)

author: m k
author_rank: Super Contributor
timestamp: November 26, 2024, 01:29:58 pm
content: So SA uses DTR/CTS handshaking, sort of.Where is PC's input buffer full.PC RTS/CTS handshaking on and DTR activated.CablePC____SAGND -- GNDTxD -> RxDRxD <- TxDRTS -> CTSCTS <- DTRDTR +DSR ¦> DCDDCD +Seems that HP is obfuscating.

author: Bicurico
author_rank: Super Contributor
timestamp: November 26, 2024, 05:38:05 pm
content: Sorry to OP, I have been busy at work and with family, so I have not paid much attention to my spectrum analysis hobby.I had no problems connecting to the hp 8594E via its serial port, but I am using a REAL serial port and not a simple USB serial port. These only have GND, RX and TX. So any sofisticated connection with handshake won't work.