Hi Secware_Tech6, thanks for the reply. This problem is really frustrating me as I cannot see why it is happening. Some facts:
Remote access was working until a few weeks ago. I had not changed anything when it then stopped working.
Test message are still responded to in the usual way. I.e. both STATUS and INPUT 1 still receive a response.
If the alarm is triggered the dialler does dial out, and pressing '5' appeared to acknowledge the call. I need to do it again to check, but it does appear to be 'listening' to tones.
I haven't yet tried pressing 9 after pressing 5 to enter the remote control menu after alarm activated, but will do. This should tell me whether it is not accepting the User Code, or not listening to tones.
The User Code does work when directly entered into the keypad on the dialler. I have tried changing the User Code, but it made no difference.
I have checked that 'Remote Access' is enabled in settings
I have tried calling from two mobiles on separate networks (Vodafone and Tesco/O2). No difference.
The dialler has a Global M2M sim - multi-network so it may have changed network? Do you think that if it moved to a different network it may have caused this problem?
Thanks, Mike