What is a SIP trunk?
SIP trunks are connections that link a business IP-PBX to the
PSTN (Public Switched Telephone Network). Through an (ISP)
Internet VoIP connection signaling goes from the business phone
system to the SIP (Session Internet Protocol) provider
as a virtual phone line, who then connects and establishes voice calls.
The trunk connects to the PTSN. SIP trunks are much more cost
effective than traditional types of phone services. They can lower
phone costs using "unlimited" plans, as well as pay by the minute
plans with lower bulk minute rates. Some providers offer
exceptionally low rates for particular regions or
countries.
SIP trunks are virtual phone lines which
can be used to place and
receive phone calls over the Internet to anyone in the world with a valid phone
number.
SIP trunk service is significantly less expensive than traditional business telephone lines. Sometimes as much as 60 to 75% lower.
The number of SIP
channels needed by a business will depend on the type of
business and their call activity. Additionally, it will depend on
the provider and how they construct their pricing. Typically each SIP
trunk can transmit a number of SIP channels. Each channel is capable of
transmitting one call. SIP providers typically offer customers options to
subscribe to a specified number of SIP channels.
Since one SIP trunk
is capable of an unlimited number of channels, you would merely require
one SIP trunk with a specific provider. However, incorporating several
SIP trunks, each from a different provider offers increased benefits by
setting up cost effective call rules.
Using a VoIP PBX appliance with SIP Trunks
Configuration of SIP trunks can be done by tech savvy people and providers often offer guidance.
A small office with three people would require one trunk per person if all three were on the phone at the same time. As an office size increases the ratio of trunks per person would likewise decrease to about sixty percent. Call centers and high call volume businesses would need a high ratio of trunks or active virtual phone lines to working employees.
Pros of Using SIP trunks:
- Lower call costs: Select SIP providers with low costs per minute or by a region or country.
- Low cost unlimited plans: Select a SIP provider with one low monthly cost for an unlimited number of minutes. (Many of these plans include the lower 48 US states and portions of Canada.)
- Scalability: Increasing or adding trunks is quick and easy.
- Multiple Carriers: SIP trunks can be set up for different SIP Providers from the same IP-PBX for both cost efficiencies and failover.
- Disaster Recovery: Using SIP trunks calls can be rerouted instantly.
- Shared Resources: SIP trunks use the businesses' Internet connection which dynamically allocates bandwidth to active voice calls, otherwise it's used for other apps.
- Less Maintenance: There is no need for PSTN (or PRI) hardware, copper phone lines or circuit boxes.
Advantages of a VoIP PBX appliance using SIP Trunking Services
Call Anywhere for the Lowest Costs
For businesses that generate lots of International calls SIP providers can supply unlimited calling plans to many countries or incredibly low rates. The most cost effective approach to International calling is by incorporating SIP trunks. Some providers offer incredibly cost effective services to certain parts of the world. For instance a pharmaceutical supply company that does significant business with firms in India might pick a well established Indian SIP provider. SIP trunking empowers companies to gain access to these providers. Using SIP trunks between multiple offices on the same VoIP system become free Peer to Peer calls.
The Greatest Flexibility and Control
SIP trunks offer the most flexibility of any phone services. The precise nature of SIP allows for multiple trunks from numerous providers to be added or subtracted instantaneously. The instant flexibility provides concise control by scaling trunks as needed using the most cost effective providers.
Instant Failover and Disaster Recovery
Regular analog trunks (PSTN phone lines) can go down from bad weather or inferior circuits. These instances routinely require a few hours minimum to correct, especially for PRI circuits. SIP trunks offer immediate virtual failover lines where calls can instantaneously be routed. Once setup these Outbound Call Rules configured in the VoIP appliance do not require administration or time consuming maintenance.