TTL - RS232 Testing

[CheesyPeteza]

I made the cable for connecting to my Ambit 200, but I get nothing in Hyperterminal.

I've checked all the connections and they seem correct.

Even if NTL have updated the firmware on it, it should still show something shouldn't it?

Is there any voltages I can check for to make sure the MAX233 chip is working? I'm wondering if I killed it by overheating it as I didn't use a socket for it.

Is there anyway of testing the hardware, and what should I see?

 

[CheesyPeteza]

I can answer my own question here. First of all I got it all working! Woo hoo!

But not without trouble, I think the design in the haynes manual maybe incorrect. I'll have to check again soon, but I was so excited to get it working that I haven't looked at it since then really as I was using my new internet connection.

Testing:

After building the cable you can test it by touching together the TX\RX wires on the serial RS232 side and typing stuff into hyperterminal, if you see your text being repeated back to you then you know that the connection that far and that hyperterminal is working.

After that, connect together the TX\RX on the TTL cable modem side. You need to plug it in now to get the 3.3v to power the chip. Start, typing stuff in and it should be repeated back to you. Theres a good chance loads of stuff will start spewing down the screen, as anything the cable modem displays gets turned into new commands for it.

This is what happened for me, which made me realise that the reason it wasn't working was that I had the TX & RX connections on the cable modem side on the wrong ones, so I swapped them over and it worked fine!

 

[geakem]

which chip are you using? i presume you mean an rx/tx/v/g terminal cable? get the cable modem book and the guide is great. alternatively dl the ebook...i bought it.

 

[hardcoreprawn]

Damn cables always to blame with RS232