Here is my situation. I have a client who has about 50feild officers always out of office visiting clients in different towns. There is 3G/4G internet coverage in all these towns. The officers have android handsets and I want to find out how I can give them access to Head office that has an SAMSUNG OS7400 through MOBEX and the public cellular providers. This or any other solution should prove cheaper than they phoning direct to office.

Mobex doesn't work on pstn.
Requires isdn or sip.
Do you have the we-voip client in your market yet?

I wil look it up but what i meant was mobex via 3G/4G networks

What you are after is a sip phone client (eg bria) on the reps phones, this will talk back to the system via the 3g/4g

nameless, I have an ag warehouse user on a 7100 on 4.53c here in the states. I would like to give them a few sip wireless (i.e.Grandstream DP715)as they spend a lot of time seasonally on the floor. Can I make that work as an extension? If so what steps are required, ty.

You will need mgi and 3rd party sip licenses. I would upgrade to 4.7x as dtmf will work properly then.

I haven't tried grandstream myself but have tried polycom kirk system and it worked