FXO Supplementary Services

The FXO supplementary services include the following:

■

Hold / Transfer toward the Tel side: The ini file parameter LineTransferMode must be set to 0 (default). If the FXO receives a hook-flash from the IP side (using out-of-band or RFC 2833), the device sends the hook-flash to the Tel side by performing one of the following:

●

Performing a hook flash (i.e., on-hook and off-hook)

●

Sending a hook-flash code (defined by the ini file parameter HookFlashCode)

The PBX may generate a dial tone that is sent to the IP, and the IP side may dial digits of a new destination.

■

Blind Transfer to the Tel side: A blind transfer is one in which the transferring phone connects the caller to a destination line before ringback begins. The ini file parameter LineTransferMode must be set to 1.

The blind transfer call process is as follows:

●

FXO receives a REFER request from the IP side

●

FXO sends a hook-flash to the PBX, dials the digits (that are received in the Refer-To header), and then drops the line (on-hook). Note that the time between flash to dial is according to the WaitForDialTime parameter.

●

PBX performs the transfer internally

■

Hold / Transfer toward the IP side: The FXO device doesn't initiate hold / transfer as a response to input from the Tel side. If the FXO receives a REFER request (with or without replaces), it generates a new INVITE according to the Refer-To header.