User's Manual

Protocol Operation
Crescendo VHF Half-Duplex User Manual Page 37 of 74
6.5.5 DTR Modes
In addition to the AT commands that are used to control the dial-up connection, DTR may be configured to
provide similar functionality. Only the main port supports DTR, so the setting for DTR mode on the
auxiliary port Hayes protocol is not used.
There are four available DTR modes:
 Ignore DTR: DTR is not used to control the Hayes communications settings.
 Hangup on DTR Low: If DTR is low then the radio will hang-up the current connection. If DTR is
low when a dial attempt is made, then the connection will be severed immediately after being
established.
 Hangup on DTR Dropped: If a falling edge (high to low transition) is detected on the DTR line, the
radio will hang-up the current connection.
 Local Mode on DTR Low: If the radio is online, and DTR is disasserted, the radio modem will
return to local command state, but will still remain connected. The only way to return to the online
state is to set DTR high, and then issue the ATO command. If DTR is low when the ATO command
is issued, then the radio will immediately return to local mode.
6.5.6 Traceroute
The AT commands may be used to obtain diagnostic information from the radio network. The ATT
command is used to start a traceroute diagnostic to a destination radio. The syntax of the ATT command is:
ATT<address>
Where <address> is the address of the destination radio.
The traceroute diagnostic periodically sends a query to the destination radio and expects a response. The
traceroute response will contain the RSSI and data quality of the destination and intervening repeaters. It can
be stopped by entering any character to the radio. The traceroute diagnostic will then display the number of
requests and responses in the session, and return the port to local command mode.
att1003
1000 -> (1003, -84 dBm, 255 QF) -> (1000, -90 dBm, 255 QF)
1000 -> (1003, -84 dBm, 255 QF) -> (1000, -90 dBm, 255 QF)
1000 -> (1003, -84 dBm, 255 QF) -> (1000, -91 dBm, 255 QF)
1000 -> (1003, -84 dBm, 255 QF) -> (1000, -90 dBm, 255 QF)
1000 -> (1003, -84 dBm, 255 QF) -> (1000, -90 dBm, 255 QF)
Tx: 23 Rx: 23 Lost: 0 (0.0%)