Command Line Interface
Command Line Interface Convention
Hardware Switching to Maintenance Mode
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Happy Flow
1. In data-mode the unit starts looking for the Escape-sequence if there is no data from DTE for
more than 20 ms (Start Guard Time).
2. If the unit detects the Escape-Sequence:
• The transmitter continues sending over the air the data received from DTE before Escape-
Sequence and buffers the data from DTE;
• The Receiver immediately stops forwarding to DTE the data received over the air and buffers it
instead.
3. The radio unit waits for 20 ms and then sends Escape-Acknowledge to DTE if there is no data
from DTE during 20 ms of Stop Guard Time.
4. The unit goes to Maintenance mode and discards Escape-Sequence from input buffer. The modem
is immediately ready to receive commands. At the same time it continues buffering the data
received over the air since step 2.
Escape-Sequence in Data
During its waiting in step 3, the unit receives data from DTE:
• The unit sends buffered Escape-Sequence from DTE to the air;
• The unit sends all buffered data received from the air since step 2 to DTE and stays in data-mode
(i.e. transmits data received from DTE over the air – including the just received, unexpected, data
and forwards data received over the air to DTE.)
4.1.2. Hardware Switching to Maintenance Mode
As alternative to Software Switching, the switching through the MP/DP control line can be used (this
control line can be also used as Data Terminal Ready, DTR). To set Maintenance mode, the DTE must
assert DTR signal active (0v level). By falling edge of DTR signal the unit goes to Maintenance mode and
then sends Escape-Acknowledge to DTE („@00<CR><LF>“).
20 ms toggling on CTS control line followed by Escape-Acknowledge response is needed to
acknowledge switching from Data to Maintenance mode and vice versa. In Maintenance Mode, the unit’s
serial port must keep Clear to Send (CTS) line always active (see also “MPORT” on page 22).
Note:
The powered up radio modem by default goes to Data Mode regardless of DTR control line polarity.
4.1.3. Switching to Data Mode
• DTE sends the CLI command “DATAMODE<CR>” or „DATAMODE<LF>” to the unit.
Note:
Command “DATAMODE<CR><LF>“will be accepted as command “DATAMODE<CR>” and Data
Byte=0x0A.
