Product specifications

Features
3-2 80-99240-1 Rev. D
AT Commands
The GSP-1620 modem can be controlled using standard AT
(modem attention) commands, which are listed in Chapter 4.
Modes of Operation
The GSP-1620 modem has two serial ports: one for Data and
one for Control. The modem can be set up to use the Data port
only or both the Data and the Control ports.
• If solely the Data port is used, AT commands can be sent
to the modem only when there is no data session active.
• If solely the Control port is used, only AT commands can
be sent to the modem (no asynchronous or PPP data).
• If the both the Data and Control ports are used, the DTE
can receive data on the Data port and, at the same time,
communicate with the modem on the Control port using
AT commands.
Using both the Data and Control ports allows more
sophisticated communication with the modem and thus
better control of it.
Short Messaging Service (SMS)
The GSP-1620 modem supports IS-637 Mobile Terminated
Short Messaging Service (SMS). This is a separate feature
from data (packet and/or asynchronous), and may be billed
differently by the Service Provider.
Mobile-terminated SMS allows the host application to “send”
numeric, alphanumeric, or binary messages to the GSP-1620
modem. These messages are passed transparently out the
Data or Control RS-232 ports to the DTE (the SCADA
application). The modem makes no attempt to construct
ASCII character data. If “control” data is sent to the modem
via the SMS option, it will be passed along transparently to
the DTE (SCADA application).