Supported VoIP/FoIP Protocols

Supported VoIP/FoIP Protocols

We allow users to send calls with either SIP and IAX protocols for voice communication.

T.38 fax protocol is also available in those DID zones where this is supported.

VoIP and FoIP require two-way transmission of data using Internet Protocol (IP). Our platform strictly adheres to all protocol standards for maximum quality of service.



T38 (where available)


SIP - Session Initiation Protocol

The Session Initiation Protocol (SIP) is a signaling communications protocol, widely used for controlling multimedia communication sessions such as voice and video calls over Internet Protocol (IP) networks. The protocol defines the messages that are sent between peers which govern establishment, termination and other essential elements of a call. SIP can be used for creating, modifying and terminating two-party (unicast) or multiparty (multicast) sessions consisting of one or several media streams.

IAX - Inter-Asterisk Exchange Protocol

IAX is a communications protocol for setting up interactive user sessions. In IAX, handshaking is not required when a call is initiated, which renders the communication vulnerable to denial-of-service (DoS) attacks. However, the risk can be reduced by the use of firewalls, passwords and other standard security countermeasures.

T.38 relay standard

The T.38 fax relay standard was devised in 1998 as a way to permit faxes to be transported across IP networks.