Having been in the Telecom field for well over twenty years, we were always saddled with certain decisions when it came to trunks to PSTN (Public Switch Telephone Network).  If you could live with marginal voice quality or didn’t have the budget to pop for a T-1 voice circuit, you had few options.  Your choices were between using POTS lines, CO (Central Office) trunks, or tie trunks if multi-location. These were typically analog with a snap, crackle, pop reminiscent of Rice Krispies. 

The other choice was a voice T-1 or PRI flavor, both of which we were more expensive, but as it was digital, it was crystal clear and the bonus was it only used four wires for 24 phone lines or 23 for PRI (ISDN Primary Rate Interface). Heck, even I paid for PRI though I did not have a need for all the lines as I could not accept sacrificing call quality.

Fast-forward to today and Session Initiation Protocol, aka SIP. There are a lot of cool things about it, but it’s important to understand its current form of implementation.  It can also be implemented in a couple different manners. It can be delivered by your carrier over Ethernet, but don’t think that it will conflict and turn into a VoIP chattering, as it comes in on its own circuit. Alternately, as it is a protocol, it can also be delivered over existing MPLS circuits for multi-location businesses as long as QoS is enabled.  Important to note is that the SIP connection provided by your carrier is from your phone system/PBX to the carrier. The calls to the outside world are still carried through PSTN so the quality will remain acceptable.

What is so cool about SIP? First off, it handles both voice and video. But here is the really neat thing, much like a SuperTrunk  of days gone by or the PRI of today, if you need less that 20-some lines, but want the robust DID (Direct Inward Dial) functionality, SIP trunks are for you.  Here’s a real scenario. I pay $250 per month for a PRI, but I can get 5 each SIP trunks (at $12 each for 3-year commitment) for $60 a month!  This will save me $190 per month and that’s a good thing – a real good thing!

SIP trunks may not be for everyone and may not even be available in your area, but if considering a new phone system or a new carrier, you should at least consider SIP trunks. If you’re simply changing telecom carrier and want to entertain SIP trunks, you will need to check to see if your phone system is SIP-trunk ready and capable.  Those pesky details!

If you want to know more or if you area or phone system is SIP-trunk ready, feel free to give us a call.