SIP trunk

SIP stands for Session Initiation Protocol. It sets calls up and tears them down; the speech itself is carried as a data stream. A trunk bundles several simultaneous calls and one or more blocks of phone numbers. It has replaced the ISDN lines that phone systems used to be connected to.

For AI telephony, a SIP trunk is the direct way to connect an existing phone system to an assistant: the phone system or the provider sends selected calls to the assistant via SIP, and the assistant can hand them back into the phone system. Compared with simple call forwarding, more information is preserved, such as the caller’s number. In return, the setup is more technical and usually needs support from the phone provider or the IT department.