User guide

33
6615-2203
GSM
Network
NOTE: If no valid DTR signal can be provided by external application, the modems DSR signal can
be used to trig the transmission. Connect the DSR signal via a relay, or other potential
free contact, to the DTR signal. A 10 kohm pull down resistor should also be connected
between the DTR and a signal that is always low e.g. the DCD can be used if the modem
is used only for SMS sending:
DTR
DSR
DCD
Relay
External
application
10 kohm
May be required in harsh environments.
Application examples
… GDW-11 connected to GDW-11 with DTR signal call
Configure the units
AT+CPIN=xxxx If PIN code required
AT&F Set the unit to factory default
AT&W Store default settings
Set up the connection – The dialling modem
AT+CPBS=”SM” Select phonebook as memory storage (this is default)
AT+CPBW=1,”nnn” Store the number of the remote modem in the dialling GDW-11
AT&S0 Set DSR signal always high (if this signal is used to trig the DTR)
AT%D1 Activates automatic DTR dialling if DTR switches from low (OFF)
to high (ON).
AT&W Save settings
Switch DTR from
OFF to ON
The modem will now dial the phone number stored in the first location of
the phonebook.
Set up the connection – The answering modem
ATA Enter the answer command when RING comes from the network or
set up ATS0=1 to auto answer on 1 RING signal (or more than 1).