SDT 5000 User Manual
Document MBUD-0109v11
6.2.2 AT COMMAND MODE
The AT command mode implements a subset of the industry standard AT command set. All
commands are prefixed by the “AT” string and terminated with a <CR>. The AT command mode
can be used by an RTU which expects a standard AT command set telephone modem. The
telephone number dialed is set to the X25 address of the host.
Once a call is established the unit goes into a data state where data sent in the RTU is transmitted
to the host and data from the host is transmitted to the RTU.
Messages from the host to the RTU are not constrained in length. The data is sent to the RTU as
each X25 packet of data is received by the SDT 5000, regardless of the M bit. Messages from the
RTU to the SDT 5000 are not constrained in length, as a complete packet of data is received by
the SDT 5000 the data is sent to the host. Messages are delimited by an inter-character time equal
to the value specified in the S-register 12.
6.2.2.1 Configuring AT Mode
AT mode is configured with the ‘atcfg’ command. Please refer the SDT 5000 command
reference document for a detailed explanation of the command and command line facility.
The values shown below reflect the factory defaults. These values may be modified via the
standard AT commands. These values may be updated with either the ‘atcfg’ command or
when the AT&W AT command is issued on the RTU port. The values will become active
when the ‘ATZ’ command is issued.
To check the current configuration enter the following command:
>atcfg
CECHO ,W,Command echo : YES
DECHO ,W,Data echo : NO
RESULT,W,Result codes : All
VERBOS,W,Verbose : YES
DCD ,W,Data carrier detect (DCD) mode : ASSERT
DTR ,W,Data terminal ready (DTR) mode : OFF
DSR ,W,Data set ready (DSR) mode : ASSERT
BAUD ,W,RTU port baud rate : 9600
PARITY,W,RTU port parity : NONE
DATA ,W,RTU port data bits : 8
STOP ,W,RTU port stop bits : 1
TXFLOW,W,Tx flow control : NONE
HWFLOW,W,Rx hw flow control : NONE
SWFLOW,W,Rx sw flow control : NONE
A description of the parameters is shown below:
Command Echo
The command echo flag is the default value used for the ‘command echo’ in
AT mode. The user via the ATEn command on the RTU port may modify
this value.
Version 1.1, 03/24/06
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