RS232-USB converter testing

[Davey-T]

Does anyone know if it's possible to test a RS232 to USB converter.

I bought one from Maplins with a Prolific chipset but it doesn't seem to work although Device manager reports "device is working".

Dave

[HAL9000]

Don't know about 'testing' it but did yours come with drivers? I bought a maplin one last year that didn't have any software, worked with my old Vista laptop but new Win 7 one didn't like it (similar issue to you) until I downloaded a driver. Works fine now. I seem to remember it took a while to find online so if you want the file I can email you. If there's something else wrong then I'm afraid that's where my knowledge ends! Chris.

[HAL9000]

Sorry the computer it worked on straight away was WinXP not Vista.

[pete_l]

You could try connecting its TxD pin back to the RxD and seeing if what you type is echoed back to whatever terminal program you are using. Just make sure to tuen off LOCAL ECHO before you do this.

[Davey-T]

Don't know about 'testing' it but did yours come with drivers? I bought a maplin one last year that didn't have any software, worked with my old Vista laptop but new Win 7 one didn't like it (similar issue to you) until I downloaded a driver. Works fine now. I seem to remember it took a while to find online so if you want the file I can email you. If there's something else wrong then I'm afraid that's where my knowledge ends! Chris.

Downloaded Win7 64bit driver said it had found software etc

Dave

[Davey-T]

You could try connecting its TxD pin back to the RxD and seeing if what you type is echoed back to whatever terminal program you are using. Just make sure to tuen off LOCAL ECHO before you do this.

Sorry Pete, could you expand a bit on your post, can I download a terminal program to test it

Dave

[damnut]

W7 is very choosy over which Prolific chipset it will see. If it works in XP and not in your version of W7 its worth returning and getting a converter that is w7 cert. Used to use spare xp laptop to drive my 10" lx200, the converter would not work at all with w7.

[pete_l]

Sorry Pete, could you expand a bit on your post, can I download a terminal program to test it

Dave

The program you want is called Realterm.

Once you have it installed, you need to find out, guess or use trial and error to find the USB port your device is showing up as.

Step 2 is to connect a wire between the TxD pin on the serial end of your converter to the RxD pin. See here fror a diagram.

Step 3 is to open the port in Realterm, make sure LOCAL ECHO is disabled and start to type stuff on the keyboard.

The characters you type should go out the USB port, out of the TxD pin, back in to the RxD pin and back onto the Realterm screen - as if they'd been sent from a piece of connedted equipment. This is known as a "loopback test"

The nice thing about it is that it doesn't require you to know the communications parameters: Baud rate, parity, 7/8 bit, number of stop bits (1 or 2) as they will be the same for what you send as what you receive.

If that test works, you know your hardware is OK and your computer can talk to (and listen to) it properly. If it doesn't, sorry but you're on your own

Once you have proved that step. Connect the converter to your equipment and try typing commands by hand. Once you have the right Speed and Parity you should start to see sensible data coming back. Almost everything these days uses 8 bit, 1 stop. no parity - but the speed could be anything. If you don't know what the speed should be, try 9600 first, then 115200, then all the rest.

If you don't get any response, make sure the right pins go to the right connections on your gear. Sometimes it gets confusing whether documentation is refering to the Transmit Data pin on the equipment or on the computer.

[gvamax]

I just installed an Aten (UC-232A) serial to USB converter on a Windows XP laptop. Cost approx. US$ 20.- Don't know what chipset it uses ... Works just fine, configured itself as COM4 and connected right away to my StarryNight Pro to drive a Celestron Omni XLT 150 telescope. Must have some algorithm to figure out baudrate and the other params. A pleasant surprise !

[Davey-T]

Thanks for info Pete, will give it a go at weekend.

Dave

[Davey-T]

So downloaded Realterm connected RS232/USB converter and joined pins two and three and it doesn't type anything. Don't know if it's the device or driver problem so I've ordered FTDI converter to try .

Dave

[JamesF]

I'm a fan of the FTDI devices. They just seem to work without any bother.

James