Alcatel-Lucent 1643 AMS Applications And Planning Manual page 120

Operations, Administration, Maintenance and Provisioning
HDLC-transparent DCC
The 1643 AM / 1643 AMS systems support one bidirectional HDLC-transparent DCCR
connection between the two STM-1 line ports. Note that, selectable per port, either the
MS channel or the RS channel can be used at the same time. This feature facilitates
the interworking with third party equipment.
AITS/UITS protocol on LAPD
The user can select the LAPD protocol (ITU-T Q.921) for OSI layer 2 to be based on
AITS (Acknowledged Information Transfer Service) or UITS (Unacknowledged
Information Transfer Service). In the AITS mode the receive side sends an
acknowledgement back to the transmit side, if a data packet has been received. If this
acknowledgement does not arrive, the transmitter sends the packet again. In the UITS
mode no acknowledgements are sent.
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5-6 Alcatel-Lucent - Proprietary
See notice on first page
Operations Overview
365-312-801R7.2
Issue 3, May 2007