Electronics 2000

Hello to everybody, my name is Steve and I live in the West Midlands. I am hoping that one of you fine members may be able to help me
I have two alarm systems in my small business premises, a wired system with an auto dialer connected to my phone line, the auto dialer is triggered by a negative input from one of the sirens when the alarm goes off.
Upstairs I have a newer separate wireless system with a GSM auto dialer and pay as you go SIM card built in to the control panel.
My problem is that the auto dialer on the wired system has given up the ghost so I thought I would just put the negative input in to my wireless control panel and save myself a couple of hundred quid
Alas, the control panel on the newer wireless system will not take a wired input trigger
My question is, can I trigger one of my wireless PIR's or wireless Door/Window contacts with a wired negative input?
It seems a shame that the wireless system has a perfectly good auto dialer that could accommodate both systems if only I could trigger it from the wired system.
If any of you knowledgeable experts have any suggestions I have my soldering iron in hand, ready to rock and roll
I would be most grateful for any help.
Cheers
Steve

Maybe ask on an alarm forum such as here:
http://www.diynot.com/forums/viewforum.php?f=31

Sometimes the auto dialer uses a battery to help the memory store the numbers- might be just a dead battery (a disc type thing usually)

You could probably trigger it with a sound pick up sensor IE the sensor would hear the alarm downstairs go off and kick off the upstairs alarm
Sound sensors are quite useful for hearing breaking glass etc but can be irritating if they are put in the wrong place and pick up innocent noises like the fridge going on etc..