Unfortunately it looks like the phone module I bought either doesn’t work at all, or there is some secret to using which I’m not aware of.
I’ve used the USB serial adapter (see below) to have a good probe around the various pins and try as I might I can’t get it to give any kind of response. I’ve tried various baud rates but there is no sign of anything coming back from the device. I’ve tried swapping the TX & RX pins over so that I am connecting TX to TX. This seemed a bit better in that I got an error message coming back from the serial console (UART overrun) but other than that no signs of life.
This is not helped by the lack of documentation. I will try contacting the Chinese seller but given how long I’ve had it (I got it in April) I don’t think I’ll get much back.
However there are two bits of good news:
i) The small USB serial interface and breakout cable is very nice and I’m sure I’ll find it useful in future
ii) I’ve had some very helpful comments from Andy (see older posts) who has bought a different module and got it working. So I’m following suit.
I’ve ordered these from ebay:
The left is a SIM800L GSM module, and the right is a ‘DC Buck’ regulator. The GSM module looks much smaller and nicer than the one I have, and the reason for the regulator is that it needs 5V and I’ll need to step down the Aux power output from the Texecom panel which is 12V.
Andy reports that everything works fine with the panel and these modules, so I’m very pleased to find the concept is proved and I’m looking forward to trying it for myself.
Meanwhile if anyone has any idea about how to configure the TC35 I’d be glad to hear them.