User's Manual Part 1

40 Specifications Modes of Operation
Revision 1.8 P/N 90023363
Modes of Operation
The following modes of operation are listed and described below:
• Sleep
• SMS Messaging
• Circuit Switched
• GPRS Data
• Standby
Sleep
SLEEP mode provides the user with enhanced power savings by suspending unused
services while powering down other portions of the device. This power savings mode
occurs automatically and is transparent to the user. SLEEP mode can have a
considerable effect on the useful operating intervals between recharging. The modem
draws its power from the host thus affecting the host’s operational time.
SMS Messaging
SMS Messaging utilizes a very small portion of the data stream to send text-based
messages to units actively connected to the network. SMS Messages can be received in
either Standby, GPRS Data or Circuit switched modes. This feature provides a method of
sending text messages between network devices or other devices connected via the
Internet. SMS messages are limited to 160 bytes of data.
Circuit Switched
A circuit switched session is initiated through a dial command (user initiated) or an
answer command (remote initiated). In both cases the modem sets up and maintains a
continuous data connection between the modem and the remote. This connection is
maintained regardless of whether data is being sent or received. The session can be
terminated by the ATH command or through DTR control.
During a circuit switched session the modem will not enter sleep mode.
GPRS Data
The GPRS data connection provides the most cost effective and efficient way to send
data over a GSM Network. The modem can chain together multiple slots to increase its
throughput, the charges are applied only to the intervals when sending data thus the
5 Ground 0.0 Yes
6 Programming VPP NC or VCC Yes
7 Data I/O 0.0 to 3.0 VDC Yes
8 No Connection NC No