Viewpoint of DIS(DTS)/DCS
Before starting communication, the sender and the receiver communicate their functions to each other before starting communication, and determine the communication function and speed.
The receiving side fax machine transmits its own function to the sending side fax machine by the DIS signal. The sending fax machine receives the DIS signal from the receiving fax machine, selects the maximum function set by the sending side, which is a function that can be used by both the sending and receiving sides, and receives the selected communication mode using the DCS signal. Send it to the side fax.
By checking the DIS (DTC) information, you can find out the contents of the capability declaration of the receiving fax machine, and by checking the DCS information, you can find out the communication mode selected by the sending fax machine.
Protocol monitor log is recorded and printed in one communication. If the protocol log becomes too long to fit on one page due to multi-page communication, the first protocol log will be deleted and only the last protocol log will be recorded and printed.
DIS(DTC)/DCS records and prints on top of the protocol log so that the contents can be seen even if the first protocol log is deleted.
Fax communications are created according to ITU, and the main ITUs involved are T30. and T4.
Documents of these recommendations are published online and can be downloaded from the following sites.
 Check Point / チェックポイント |
The documents related to the ITU Recommendation on Fax Communications are as follows.
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DIS(DTC)/DCS reads the contents of FIF (Facsimile Information Field) by referring to the bit assignment table of DIS(DTC)/DCS. The bit assignment table for DIS (DTC) / DCS is described below.
- T.30 Document facsimile transmission procedure on the general switched telephone network
Facsimile Information Field (FIF) / JT-T30 (ITU-T T.30)
Table5-1 /JT-T30 (ITU-T T.30) Page 84