Adtran TA850 or 6XX series.
Depending on how your phone system takes in a signal POTS or PRI/T1 . The Mux (adtran or similar product) will terminate the circuit and the voice portion can hand off as POTS via Amphenol cable to an rj21x or 66 block, or there will be a DSX (T1) handoff to your phone system. There will also be a LAN port to handoff to your firewall internal router, depending on IP needs you can bridge it or have a Public IP on it which will be your routers or firewalls gateway. There are some providers that sell a "dynamicly allocated circuit" where you have the full 1.54MB to use for data when youre not on the phone, and little data overhead when a call is taking place. Thats code for VoIP, you should'nt be afraid of that, you may get a better deal on that. You are getting true QoS because the provider is providing the pipe. If that's the case, it may be an Adtran TA 900 series )916,924 or something like that. It could also be a Cisco. Good luck!
