Software Switching To Command Mode; Hardware Switching To Command Mode; Switching To Data Mode - Javad HPT435BT User Manual

The command is not valid for specific radio model. To display the list of available commands,
0x04
the HELP command must be used.
0x05 Unspecified Error

Software Switching to Command Mode

On power-up the radio modem is in data-mode. To switch to command
mode the special byte-sequences with special meanings are used:
• Escape-Sequence: "+++" with 20 ms guard time before and after the
command characters
• Escape-Acknowledge: "@00<CR><LF>"
20 ms toggling on CTS control line needed to acknowledge switching
from Data to Command mode and vice versa.
Happy Flow
• In data-mode the unit starts looking for the Escape-sequence if there
is no data from DTE (Data Terminal Equipment) for more than 20 ms
(Start Guard Time).
• 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.
• 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.
• The unit goes to command 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.)
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Hardware Switching to Command Mode

As alternative to Software Switching, the switching through the MP/DP
(Data Terminal Ready, DTR) control line can be used. To set Command
Mode, the DTE must assert DTR signal active and then passive. By fall-
ing edge of DTR signal the unit goes to command mode and then sends
Escape- Acknowledge to DTE ("@00<CR><LF>").
20 ms toggling on CTS control line needed to acknowledge switching
from Data to Command mode and vice versa.
Note: The powered up radio modem by default goes to Data Mode regardless of DTR
control line polarity.

Switching to Data Mode

• DTE sends the CLI command "DATAMODE<CR><LF>" to the unit.
• Unit answers with Escape-Acknowledge („@00<CR><LF>") and
immediately goes to datamode, so that the DTE can start sending data
as soon as the Escape-Acknowledge has been received.
• If no valid CLI commands received from DTE within 1 minute, the
unit will automatically switch back to data-mode.
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