PURPOSE: To shorten time for a transmission procedure by setting code information corresponding to a transmission function, which is exchanged by a converting means, into the information field of a non-standard function setting signal or a non-standard function instructing signal when it is responded that a call terminating side is equipped with the converting means.

CONSTITUTION: A system memory 2 stores a conversion table to convert a function information data, which is set to a facsimile control field FIF, to a function code data expressing the type, and by using the function code data as the function information data to be set in the facsimile information field FIF of a non-standard function identifying signal NSF, non-standard function setting signal NSF and non-standard function instructing signal NCS, the information amount of the function information data can be reduced. Then, the time for the transmission procedure is shortened.