SIP (Session Initiation Protocol) Trunking allows companies with an in-house PBX to upgrade to Internet phone service for both internal and external phone calls.
A SIP trunk attaches to an in-house PBX or an adapted traditional PBX and then translates all incoming and outbound calls into cheap Internet calls. This means that all calls in-house are free and outside of the office are cheap VoIP calls, which can save companies thousands of dollars each year.
SIP trunks are perfect for companies with a large number of extensions with a relatively low volume of simultaneous external calls, because businesses can buy SIP trunks based on the number of concurrent external calls rather than subscribe for hosted VoIP extensions for each employee.
For instance, if a company has 25 employees and subscribes with a hosted VoIP PBX provider for $19/month per extension, even though the company only experiences 8 concurrent calls at any given time, that company is going to spend about $475 each month.
If a company has 25 employees and only expects a maximum of 8 concurrent calls, they only have to subscribe for 8 SIP trunks. If the SIP trunk is $15/month per trunk, this means that the company only pays $120 each month. That’s a monthly difference of $355!
The trade off with investing in a SIP trunk is that companies will have to manage an in-house IP PBX. Still, a SIP trunk system does include a deeper feature set. These include:
- A more detailed auto attendant
- Better audio conferencing
- A more business-rich voice messaging system
- And other in-depth features
Any company with 20 or more employees should consider a SIP trunking as a money-saving option.
Benefits of a SIP Trunk
The best benefit of a SIP trunk is cheaper external calls. SIP trunks are a favorite of companies that already have PBX technology and would rather adapt their current hardware with a SIP trunk instead of investing in a hosted PBX, which is hosted off-site and includes SIP trunk technology.
The many benefits of SIP trunking include:
- Low-rate long-distance and international calls
- Consolidated extensions
- Elimination of IP-PSTN gateways: SIP trunking directly connect to the Internet without going through the Public Switch Telephone Network (PSTN), so IP-PSTN gateways aren't needed
- Eliminate BRI and PRI (Primary and Basic Rate Interface, respectively) subscription fees: SIP trunking involves a direct connection to the ITSP, so BRIs and PRIs can be replaced (this saves a lot of money).
And of course, by choosing a SIP trunk, businesses have access to all of the benefits of Internet phone service. These additional features include:
- Caller ID
- Call or media transfer
- Call conference
- Call hold
- Call recording
- Call routing
- Do Not Disturb
- Remote extensions
- Push to talk intercom
- E911 capability
- Auto attendant
- Local number porting
A SIP trunk makes it easy for companies with existing hardware to upgrade to cheap Voice over IP phone service and enjoy all of the perks of Internet calling for in-house and out-of-office.