Testing an ST4 Cable

[Stephen]

After a frustrating night of being unable to guide, I started to come round to the conclusion that my ST4 cable may be at fault.

PHD and QGVideo would not move the mount through either my QHY5 or the 314L (as a test.)

However I've just put the ST4 cable in the back of my adsl modem, and I'm still connected to the internet

Is this a suitable test for the cable, or could there be other issues that wouldn't show through a modem test?

Cheers

[Merlin66]

The ST-4 cable is wired so that pin 1 is connected to pin 1 at the other end. The "modem" cables appear to be "crossed" ie pin1 goes to pin6 - have a good look at the colour codes on the pins/ wires.

[Stephen]

Scrap that as a silly idea then

So I got the multimeter out and verified each pin - they all seem sound.

Guess the only question is are they wired up the right way - or should one of the connectors be flipped over?

I am starting to fear the problem is higher up the chain (Guide Port / Handset / Mount)

[Photosbykev]

in a standard 9-pin serial connection pins 2 and 3 are swapped over i.e. Send and Recieve . I'm not sure if this would apply to a ST-4 cable?

[Stephen]

in a standard 9-pin serial connection pins 2 and 3 are swapped over i.e. Send and Recieve . I'm not sure if this would apply to a ST-4 cable?

No there's not pin swapping in an ST4.

However final brain wave of the evening!!!

I realised that as I have a DIY guide port, I can remove the ST4 cable from the loop, and plug the handset via the tiny 4" cable coming out of the handset directly into the QHY5.

Guess what, it all worked

Time for a follow up email to Astronomiser, I would like a new cable please!!!!!

[Merlin66]

When you look at the image you can see the top and bottom colours are swapped...

you need a new proper ST-4 cable!

[Photosbykev]

If you want to get really confused take a read of this Shoestring Astronomy Support • View topic - What is ST-4 Compatible? Is GPUSB Backwards?

[Stephen]

Just had a reply from Andy, he will repair it if I return it.