What Is a SIP Call? - An Expert's Q&A

What Is a SIP Call?

A SIP -- or Session Initiation Protocol -- call is a phone call that connects using a method of linking a Private Branch Exchange (PBX) to the public phone network by using a data network, akin to a VoIP (Voice over Internet Protocol) system, but with all of the advantages of a PBX. SIP trunking is the service provided by an Internet Telephony Service Provider (ITSP) that allows you to make an SIP call.

Why Would I Want That?

Simply put, by bypassing the public phone network's standard jacks, you also bypass their basic service rate and fees -- in other words, each SIP call saves you money.

What About Call Quality?

There was a time in which telephony call quality in general was low compared to a standard line, but that time has long since passed. Today's SIP calls are as clear or clearer than standard phone lines in almost every case -- provided they were properly setup. Improperly trunked SIP calls can suffer packet loss and latency problems that will reduce quality.

Is This Technique for Businesses Only, or Can I Use it at Home?

SIP trunking requires a very powerful internet connection and a Private Branch Exchange; if you pay for business-level internet at home (and for some reason you have a spare PBX sitting around unused) you could use it, but to be honest you're probably better off sticking with a traditional VoIP provider for your home telephony.

What Do I Need To Do To Maximize The Advantages At My Business?

To get the best call quality, you'll need a network backbone with minimal latency, minimal packet loss, and low jitter. Then, you need to connect your PBX to your ITSP's SIP trunking service. One way to get it right is you use an ISDN30 circuit and a dedicated Internet connection -- that will maximize call quality without eating away at the savings you get with every SIP call you make.

How Do I Know if My Existing PBX is Capable of Making SIP Calls?

If you have an IP-PBX, it is. If not, it still is -- but you'll potentially lose out on some of the more advanced features your ITSP may offer.

Which Internet Telephony Service Provider is the Best?

Of course, there is no right answer to that question; each has its own specialties and services -- but in general, you want an ITSP that offers business-class service, 24/7/365 telephone support, and multiple telecom carriers. Everything else is negotiable.

How Much Money Can My Business Save by Switching to SIP Calls?

That depends a lot on how many calls your business makes, at what time, the distance of the call, and how long the calls last. If you provide a potential ITSP with your most recent phone bill, they'll generally be happy to go over it with you and discuss how much they can save you. In most cases, even with a relatively small call volume, you'll find that it's quite profitable in the long run -- that's the power of the SIP call.

Business SIP Trunking Service

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