Canon FAX-L1000 - Manual (Page 522)

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FAX-L1000 Chapter 5: Appendix
Layer 3 (Continue)
Message Description Remark
REL Release Sent when layer 3 is released or when
DISC is received.
REL COMP Release Complete Sent when REL is received. ISDN sends
with the transmitted REL.
b) B-channel messages
Layer 2
Message Description Remark
SABM Set Asynchronous Balanced The first thing sent when layer 2 is set.
Mode
UA Unnumbered Acknowledge A reply message for SABM, DISC.
DISC Disconnect Sent when layer 2 is released.
Layer 3
Message Description Remark
CR Call Request Sent when layer 3 connects.
CN Incoming Call Received when layer 3 is connected.
CC Call Connected Reply for CR.
CA Call Accepted Reply for CN.
SQ Restart Request Sent before layer 3 connects.
SI Restart Indication Received before layer 3 is connected.
SF Restart Confirmation Reply for SQ/SI.
CQ Clear Request Sent when layer 3 disconnects.
CI Clear Indication Received when layer 3 is disconnected.
CF Clear Confirmation Reply for CQ/CI.
Layer 4
Message Description Remark
TCR Transport Connection Sent when layer 4 connects.
Request
TCA Transport Connection Sent when TCR is received and layer 4 can
Accepted be connected.
TCC Transport Connection Clear Sent when TCR is received and layer 4
cannot be connected.
TBR Transport Block Reject Sent when an error is found in layer 4
information.