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Chapter Four
Configuration
Page
43
The module starts up in command mode and waits for a command from the host device. An
ATD command will initiate a connect command to another module.
HOST
WI-MOD
# 5
HOST
WI-MOD
# 8
For example, ATD8 to module #5 will initiate a connect command to be sent to module #8.
Module #5 will respond with RINGING to its host. If #8 is not already connected to another
module, it will connect (set DCD) and respond to #5. Module #8 will respond to its host with
CONNECT and will automatically go to operating mode. Module #5 will respond with
CONNECT to its host and will also automatically go to operating mode.
If #8 does not reply, #5 will make up to 5 attempts to connect, and will then respond to its host
with NO CARRIER. If #8 is already connected to another module, then it will respond to #5
with a “busy” message and #5 will respond to its host with BUSY or NO CARRIER (this
response can be configured under “responses”).
If there are repeater modules, then the ATD command will have the form ATDr1,r2,r3,r4,r5,d
where “d” is the destination address and “r” is a repeater address. “r1” is the repeater closest to
the master unit. For example, ATD2,3,10 will try to connect to 10 via repeaters 2 and 3. Up to
5 repeater addresses may be used. A repeater can already be connected to another module - it
can still act as a repeater for another link.
Once a connection is made (DCD set), any data sent will be acknowledged by the other module.
The connection will be broken (DCD reset) if an ACK is not received within 5 attempts to
transmit a message.
Either host may disconnect the link using the ATH command - or by using the DTR signal on
the RS232 port - refer to the AT&D command in Appendix 1.
When the link is disconnected for any reason, the DCD output at each module is reset and each
module will respond to its host with NO CARRIER - each module will revert to command
mode.
Fast operation mode.
In fast operation mode, the master and slave modules continually exchange check messages to
ensure fast operation. The lead-in time in fast operation mode is only 5 msec compared to 30
msec in normal modes. Note that repeaters cannot be used in fast operation mode.
Either auto-connect or single-connect operation can be used. Use “M3” in the AT command
instead of “M2”.
Auto-connect master AT&M3&L2&E1
Auto-connect slave AT&M3&L3&E1
Single-connect AT&M3&L0&E1