Hardware manual

80-001113 SysLINK Administrator’s Guide Page 74
Outgoing and Incoming Calls
After automatically accepting an incoming connection, the gateway will begin generating
"RING" response codes to the device at 6-second intervals. Incoming network data is
buffered until the device completes the connection by entering data mode. The device may
enter data mode either manually by issuing the "ATA" command, or automatically after
receiving the number of rings specified in register S0. If the gateway is configured such that
DCD will follow the connection status (AT&C1), DCD will remain low until the connection
is completed. If not (AT&C0), DCD will remain asserted at all times.
Outgoing calls are made by the ATD command. This initiates an attempt to make a
connection to the specified IP:port pair (see Phone Numbers below). A successful
connection will send the "CONNECT" result code out the serial port and enter data mode.
However, if the dialstring was suffixed with a ';', the modem will return to command mode
after establishing a connection. If the connection fails for any reason, the "NO CARRIER"
result code is returned.
AT Commands
All AT command strings, with the exception of the break sequence ("+++") and the repeat
command ("A/"), must be terminated with the command line termination character, defined
in S3 (default is CR). All characters before 'AT' are ignored. Unsupported commands are
ignored and generate an "OK" result code. Multiple commands may be combined on a
single line, however the AT command string is currently limited to 40 characters.
Example:
AT&FE0V0