It’s not about the difference between them but how these two services cooperate with each other. SIP trunking is a service that allows you to connect your VoIP compatible onsite phone system to the cloud to have a connectivity with the outside world. Hosted PBX is already a telephony system that operates via the Internet but you can interconnect them to use some of the hosted PBX features with SIP trunking, e.g. provide an inbound toll-free number or record calls.

SIP trunkng replaces older PSTN and ISDN phone lines and uses the Internet to transmit voice data. Key benefits of SIP Trunking are:

• – Lower cost compared to older PSTN and ISDN connections;
• – Ability to easily scale up or down with the number of channels or simultaneous calls required;
• – It is also easy to relocate as you could use your SIP Trunk anywhere you can get access to the Internet;
• – SIP Trunk can be configured to encrypt all voice data before transmission and allow for HD voice codes with significantly better voice quality to be enabled.

A SIP channel is used for one incoming or outgoing call. You can think about it as a sort of a standard phone line. Every SIP trunk can support multiple SIP channels.

Number of channels supported by SIP Trunk is limited by your Internet connection speed, but most of the modern broadband connections are capable of supporting dozens of channels. E.g. 10 Mbps connection could support about 100 simultaneous calls.

This depends on your onsite PBX and its supported codecs. If your PBX supports G.729, you only require 0.03 Mbps including overheads. Therefore, if you have a reliable connection of even 8 Mbps, you could have about 260 simultaneous calls connected. However, quality of calls will highly depend on the reliability of your internet connection, so it does not have to be very fast but it must be reliable and stable.

Even if your Internet connection goes down, you’ll still continue to receive inbound calls. This is possible thanks to diversion of calls to mobile phones. How it works: commonly a call is coming to the inbound number and then passes to SIP trunking. In case there’s no connection with the SIP device due to lack of internet connection, a call will transfer to mobile phone or any other phone number you will configure.

We offer lower rates for larger call volume accounts. For services with minimum monthly spend we deduct the minimum monthly spend amount on the 1st of each month and this amount becomes call credit on your account. There are no extra charges for calls up to the minimum monthly spend, calls over are charged at the call plan rates./p>