Question How can I tell if a 9-pin connector will work?

[swmddo]

I have a telescope with an RS232 connection (9-pin male) cable with a USB -A on the other end. I purchased a new 9-pin connector cable as the older one was too long. I thought that every 9-pin connector would match but I see now that it won't as I have tried both and only the older one works. How can I tell which 9-pin connector will work for me?

thanks.

Steve

 

[Lutfij]

Welcome to the forums, newcomer!

Could you please pass on the links to the cables you've bought and didn't work when paired with your telescope? Speaking of telescope, can you also pass on the make and model of said magnifying device?

as the older one was too long.
You could just tidy up the unused length of cable using zipties.

 

[swmddo]

The "old" cable came with the telescope and the connector did not have any manufacturer name on it. the "new" one I got was GEARMO, but it came with a mini DVD with drivers on it, and I am now trying to find a reader to get to the drivers....looks like the newer PCs don;t have those readers anymore.

https://www.amazon.com/Gearmo-Windo...+to+serial+rs-232+adapter+short,aps,84&sr=8-3

I would hate to spend $30 - $40 for just one purpose.

And yes, I had the cable zip-tied and it was causing balance issues as most of the cables were the same way. I just wanted to clean it up a bit.

The telescope is a Explore Scientific ED80 refractor, but the mount/tripod is where the connection is.. The mount is a Skywatcher.

Thanks

 

[ex_bubblehead]

I have a telescope with an RS232 connection (9-pin male) cable with a USB -A on the other end. I purchased a new 9-pin connector cable as the older one was too long. I thought that every 9-pin connector would match but I see now that it won't as I have tried both and only the older one works. How can I tell which 9-pin connector will work for me?

thanks.

Steve

There's far more to it than just the number of pins in the connector. The pins must be wired correctly end to end as well. This is where you get out the multimeter and read continuity between pins from one end to the other and compare to the documented pinout. Or, just use the working cable, coiling the excess and binding with Velcro straps (Zipties tend to cut the insulation when pulled too tight, and amateurs always tend to pull them too tight).

Another thing to keep in mind is that that USB > Serial adapter you listed does NOT handle hardware handshaking on the serial side. Check the telescope's documentation to see if it requires hardware handshaking, which would require an actual serial board be installed in the PC or, if a laptop, actual serial ports built in.

 

[Paperdoc]

ex-bublehead above is giving you good guidance. The issue here is that such a cable as your old one is NOT promised to be "standard" in any way. VERY likely the connections in it are customized for that telescope. And actually, in a USB2 Type A connector there really are only FOUR contacts to connect through to SOME of the pins on the other end. In fact, the easiest way too make a shorter custom cable will be to open up the 9-pin serial connector at that end and NOTE down exactly which wires are on which pins. Then unsolder those, cut the cable to the new length, bare 4 wire ends and solder them back to the correct pins.