Communications between SLC5/05 and Micrologix 1200

I have the task of getting a 505 to communicate to a 1200 using 2 modems and a phone line.
I have written the program for the 505 as recommended by Rockwell in the KB document G15818.

So my problem begins when the 505 dials out on the modem and the second modem rings. There is no way for this modem to answer the call without initialising the modem as it will not reply on it own.

Has anyone done this before and if so can you help me out?

Thank you,
Valeriy.

Connecting modems and PLC's together is a notorious pain in the a$$. The reason is that modems are intended to be used with a "software driver" behind a serial port on a PC. PLC's typically don't allow specific modem drivers to be loaded, especially not small ones like the 1200.

Of course it is possible to grind your way through the modem manual, sort out all the correct Hayes commands (which seem to be all slightly different from one modem to another), setup the hardware and software control in the PLC, get all the ladder logic right, test, debug, and lay waste to 2-5 days plus what remains of your hair,.... or purchase two of THESE.

If the 5/05 serial port is not in use, then you are home free, if not then this tech note is the way forward.