Interfacing modules

[wonderwall]

Hello everyone specially williamconley:D,

I just want to ask, i have searched a lot, what kind of interfacing cards does one require when connecting with

E1s/T1s(E1s/T1s interfacing module by ma vendors)
PRI/BRI(same as above)
DID(does it work on IP? if yes then should the server have internet access with some particular ports unblocked)
DOD
SIP Trunk(does the server has to have Internet access with SIP ports unblocked)

Sorry if the questions are too dumb to ask.

thanks in advance. as i am not using any server right now i cant post any info.

[williamconley]

E1s and T1s have special hardware requirements and the hardware (a card that fits in a PCI slot usually) is sold primarily by Digium and Sangoma (Digium owns asterisk, Sangoma is generally cheaper).

But neither is required (and worthy of avoiding if you can do so). E1 / T1 Telcos require leased line link. This always requires a contract and 95% of the time is a rip-off with a multi-year contract with a final monthly price double what you expected when you signed the contract. No joke. They'll use jargon and anything else to convince you that you're getting a great deal. But in the end you'll need to know this: How much will you end up paying per minute if you use 5000 minutes next month? (inclusive of all fees, minimums, taxes, surcharges, etc). If they won't give you that number, there's a reason. You'll ask, and they'll talk, but they will not tell you before they want to hang up. LOL In the end, if you do not get everything they said written into the contract, you'll want to fire whoever did the negotiations. If this is the owner, it's always a bummer. Make sure it's someone you can fire. It'll at least make you feel better while you're paying $2k/month for service that is actually only worth $427/month.

VOIP Carriers (instead of Telcos), on the other hand requires a minimum 1.5M internet connection (which CAN be through a T1 DATA instead of T1 VOICE connection ... which inevitably has a more reasonable contract, but can easily cost $300-$400 per month). 1.5 M will support roughly 15 phone call without compression. If you can get a higher bandwidth connection (2M, 4M) you can make more calls. If you compress the calls (gsm is free but crappy, g729 costs money but is compresses better and generally sounds better than gsm). Either form of compression requires more CPU than a regular call, so you may need "more server power" if you compress. This is all just through the internet. No special hardware required. Servers are actually disposable (build two, when one dies, take out the HD and hit it with the sledge and build another one).

DIDs can be acquired from almost all VOIP carriers just as they can from any T1/E1 telco. They are not different from outbound calls in any way, they are merely inbound versions of the same thing. The technical difference is that you receive them (security has to be handled slightly differently, but that's about it) rather than make them.

SIP Ports can be moved (many carriers will allow you to specify which port your calls should transmit on), but this is not common and not all carriers are very good at it. LOL

what does DOD (Department of Defense) have to do with this? LOL