What is CSID? Definition and usage

LAST UPDATE: July 29th, 2017


CSID stands for “called subscriber information.”


It is used in fax machines as a field for the receiving fax machine. It is very similar to TSID, or “transmitting subscriber information.”

When a fax transmission occurs, the CSID (receiving fax machine’s information) is transmitted to the sending machine. This information can be used in confirmation pages and fax logs.

Setting up CSID

Fax machines and fax software have fields where CSID information is inputted. It is typically the name of the fax machine as well as the phone number where it can be reached.