Automatic Fallback from Group 4 Mode to Group 3 Mode
If your machine cannot communicate with the other party using Group 4 mode, it
will try using Group 3 mode. This will allow your machine to send the message
even if you selected Group 4 mode instead of Group 3 mode by mistake.
Terminal ID
Instead of the TTI, a Group 4 communication will transmit a variety of information,
including an identifier known as the Terminal ID, which identifies the other party in
the same way as a TTI.
The contents of the Terminal ID are programmed by a service technician.
The make-up of the Group 3 TTI and the Group 4 Terminal ID is as shown below.
❐ Date, TTI, Page No., and Label Insertion are transmitted in the data signal,
superimposed on the image.
❐ Receiver (Rx) Terminal ID, Transmitter (Tx) Terminal ID, Date (Group 4), Page
No. (Group 4), are transmitted in the Group 4 handshake signals.
❐ The Receiver and Transmitter Terminal IDs have up to 24 characters. The Date
(Group 4) is in the YY-MM-DD-HH:MM format. The Page No. (Group 4) has up
to 7 characters.
TTI
Page No.
Label Insertion
Date
Tx Terminal ID
Page No.
Label Insertion
Rx Terminal ID Date
Group 3
Group 4
APPENDIX C. ISDN G4 OPTION TYPE 90
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