An extension is a short internal number. Extensions allow users to make and receive calls. You can assign extensions to every employee in your organization.
Extension types
Yeastar S-Series VoIP PBX supports the following types of extension:
SIP Extension
A SIP extension is based on SIP protocol.
To use a SIP extension, you need to enter the extension credentials on an IP phone or a softphone. After the extension is registered on a phone, you can make and receive calls.
IAX Extension
An IAX extension is based on IAX protocol.
To use an IAX extension, you need to enter the extension credentials on an IP phone or a softphone. After the extension is registered on a phone, you can make and receive calls.
FXS Extension
An FXS extension is associated with an analog phone or a fax machine. To use an FXS extension, you need to connect an analog phone or a fax machine to the FXS port of the PBX, and assign an extension number to the analog phone or fax machine.
Extension format
Yeastar S-Series VoIP PBX supports 1-digit to 7-digit extension format. The default extension format is 4-digit number.
Before you create extensions, you can go to to change the extension format and range.