Due to the fact you say Mercom units have caused you incredible pain in the past, I can tell you are an expert in this field!!!
Ex as in "has been" spert as in "drip under pressure"
I've done a bit of work with them in the past (5+ years)
The pain is caused by having to drive the length and breadth of the UK to support them
Our Mercom unit uses ISDN taps, and there is an ethernet connection from the switch as well where it can associate outgoing calls with the extensions they were placed from even though we withhold all CLIs
Thats good - you are using an out-of-band integration. Same ish principle as SMDR - the PABX tells the recorder to start (maybe - perhaps vox activated) and terminate recording. It also ties up which extension used which trunk to answer whcih call,so that the recorder can index it correctly. Is you link written by CTIgroup or versatilevoice by any chance? IIRC they did one for the index, and so possibly did one for IP Office too.
The key point to this is that the Mercom uses a high impedance tap to "sniff off" the ISDN calls and record them. It doesn't pass the information through teh recorder, it T's off it. i.e. it doesn't do any active work that affects the ISDN and PABX.
I'd be reasonably confident that, if the IPO can talk to the PSTN through the GSM gateway without issue, the Mercom won't affect it.
. I do not think that it uses SMDR for this though.
It probably doesn't!
What benefit would there be to placing the GSM gateway network side?
If you don't you'll miss any outbound calls that route to mobile through the GSM device!
PS What is D channel messaging, why would it cause an issue?
D-Channel messaging is the ISDN signalling used to pass call information from the PSTN to PABX and vice versa. That is Call setup & teardown, Dialled number info, Calling party number etc. Later versions of Mercom could decode this and use it to start & stop recordings. In general, CTI links to/from PABXs tend to be expensive items!
Can I be cheeky and ask who put the system in originally?
Take Care
Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.