The Basics of SIP Trunking
A SIP trunk lets you replace the analog (old phone) circuits with your high-speed Internet connection. You don’t have to buy new phones or new equipment.
A SIP trunk will connect your PBX (PBX stands for Private Branch Exchange, which is an acronym for your phone system) and phones when you make or receive a call. Once a call is made, your VoIP service provider's SIP Trunk will connect you to the PSTN.
SIP trunking also lets you support many forms of real-time communication in the same connection. This supports more than just voice: SIP trunking can support instant messaging, white boarding, video conferencing, and file transfer. These forms of communication are called unified communications.
A SIP trunk uses SIP, or session initiation protocol, to send and receive data.
Cost Comparison: SIP Trunking vs. Other Types of Phone Service.
There are several things you can compare to SIP trunking.
Overall, SIP trunking is much cheaper than traditional phone service (also known as POTS: Plain Old Telephone Service).
If you already have PBX phone system, SIP trunking can save you a lot of money.
If you do not have an IP PBX phone system for your business, you should consider a Virtual PBX or a Hosted PBX instead of SIP Trunking.
SIP trunks cost between $20 and $30 per user for unlimited local and inbound calling. Additional SIP trunks are needed only if you must have multiple calls at once, and you only need trunks equal to the number of simultaneous calls your business expects.
Analog circuits for your PBX and phone system typically sell for $40 each. With a traditional phone service, you also have to invest in BRIs, PRIs, and additional PSTN gateways (additional phone lines). The acronyms and the costs add up.
Adding additional SIP trunks is also much cheaper. With old phone hardware, you have to pay for an extra PSTN gateway, and extra PRI and BRI channels. Those channels also have to be installed manually.
For SIP trunking, you need to buy new lines for each concurrent outgoing call. The only other time you have to buy new lines is when you make more calls than your Internet connection can handle.
SIP Trunking vs. Hosted PBX
Which is Better?
SIP trunking requires you to have your own IP PBX equipment. This can be a very expensive investment for a small business.
Hosted PBX offers PBX features while a VoIP service provider manages the PBX off-site, but you have to pay a subscription fee (and sometimes other fees) for each user.
Your choice between hosted PBX or sip trunk depends on the size of your business.
Fewer than 20 people? Try a hosted PBX. More than 25 people? Try one of the SIP trunking providers above; you may be able to save more this way.
Protect Your Communications
Get a firewall to protect your voice and data from the Internet.
A SIP-capable firewall or a SIP-enabling edge device protects your phone network from malicious attacks. It also ensures that your connection is encrypted.