By default, the modem is set up as
AT+IFC=2,2
†
to allow hardware flow control in both
directions.
11.7 When Do I Need A Null Modem Cable?
The Land-Cellular modem's RS-232 serial port is wired to act as the Data
Communication Equipment (DCE), while a typical home computer or laptop system is
designated as the Data Terminal Equipment (DTE.) As long as you are connecting two
different devices (DCE-to-DTE), you must use a straight-through serial cable. However,
if you are connecting two like devices (DTE-to-DTE or DCE-to-DCE), it is necessary to
use a Null Modem Cable. Use the Null Modem cable to attach the modem to PDAs and
handheld computers. Desktop and notebook computers require a straight through cable.
11.8 Do I Need A Crossover Or Patch Ethernet Cable?
The CDM820i’s ethernet port is wired to look exactly like the ethernet port on the back
of a computer. If you are plugging into a like device (something wired as a computer),
then you will need a crossover cable. If you are plugging into a port that is not wired as a
computer, but looks like the LAN port on a switch or router, then use a patch cable.
11.9 What Is Dormancy?
The CDMA packet data service supports a dormancy feature. When no data is being
transferred on the air link for a period of time, the traffic channel is released. However,
PPP states and the IP address are retained. To the end-user, the network connection will
remain up, but the packet data call timer will stop. This saves air time for the user as well
as providing for better use of the CDMA system. The modem can initiate dormancy if it
is configured with the
AT+CTA
†
command before origination of the packet call.
Alternatively, the base station can also initiate dormancy.
11.10 Can I Change The Phone Number Of The Modem?
You can change the MIN by following the commands located in sections 5.3 through 5.6.
11.11 Does The Modem Require Any Special Drivers?
No drivers are required for normal operation.
11.12 Is There A Graphical User Interface (GUI) For The Modem?
Currently there is no GUI. All commands can be accessed via terminal emulation
software.
12.0 AT Command Reference
All modem functions are controlled using the same industry-standard AT commands that
are used to control landline modems. A knowledge of these commands is not required by
most users, but are provided here as a reference.
12.1 The Types Of Commands:
1. Basic AT Parameters
3. Basic Action Commands
4. Extended AT Configuration Commands
5. Cellular AT Commands
6. Land-Cellular Proprietary AT Commands
