ACC HDLC-NRM (SDLC) User's Guide

52 Chapter4
Protocol Specific Configuration
Protocol Configuration Values
This parameter governs the number of times the protocol will attempt to
retry after an error condition, before resorting to a higher level recovery
action.
Protocol Option Word
The option word enables various options to be configured for each
terminal. Usually, these options are defined for a certain device type in
the zcomdevice.txt file (see later section on predefined device types). The
option word can be overridden for a particular terminal by use of the
Option keyword following the Terminal-Definition. Refer to the ACC
Utilities Reference Guide for further information.
Each of the individual options is controlled by a single bit flag within the
option word. The option word is configured as follows:
NSP - No Slow Poll
Set to disable the normal slow poll facility for a primary station when the
terminal is down. When set for a primary station, the station will be
polled once during each normal poll cycle, even when down. For further
discussion of the slow poll mechanism, refer to the “Response Timer”
section of Chapter 3. This option is only applicable for a primary station.
SLM - SDLC Loop Mode
Settoenableloopmodeoperation.RefertoAppendixB,“SDLCLoop
Mode Option.” If this option bit is set (1), then the HDX (half duplex) bit
should also be set (1), and all other option bits clear (0).
BCT - Broadcast terminal (Extension feature)
Set to make a terminal the broadcast terminal for the port. A single
broadcast terminal may be configured on either a primary or secondary
port. A broadcast terminal’s address should be set to 0xFF.
The broadcast facility is an extension feature of the HDLC-NRM (SDLC)
basic procedures as described in ISO 4335. The broadcast facility allows
the primary controlstation to send messages without acknowledgment to
all secondary addresses on a line (if these are capable of receiving such
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Unused (0) NSP SLM BCT RTS HDX RPC TWS SEC