Data forwarding – Sierra Wireless DART 200 CDPD Modem User Manual

Page 102

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DART 200 CDPD Modem User’s Guide

8 Application Programming

Sierra Wireless, Inc.

8-8

Auto-Registration when not registered

This function is the same as Auto-Registration at power-on, except that
in addition to executing AT\R4 command, the timer value is set to zero.
This causes the modem to auto register at power-on, and also when it
loses registration. Setting S-Register 13 to zero with an ATS13 = 0
command suppresses the time-out function, and causes the registration
attempt to go on until it is successful.

This type of registration does not block the AT command interface so
other commands can be executed when auto-registration is in progress.
After making and saving this setting with an AT&W, power cycle or
restart the DART 200 by an AT-R to activate the function.

Auto-Registration/De-Registration at connection/disconnection

This function minimizes the time a modem is registered on the network
by linking registration to connection establishment and de-registration to
connection hang-up. This option can only be used with protocols that
establish point-to-point sessions, such as TCP and telnet, and then only
with client systems; a server must always be registered for connection
requests to be directed to it.

This feature is activated by the AT\R2 command which turns on bit 4
(value = 16) of S-Register 57, and must be followed by an AT&W
command to save the setting. This feature can be deactivated by the
AT\R3 command.

Deregistration

The DART 200 can be de-registered at any time by executing the AT\R0
command; however, doing this deactivates the auto-registration feature
of the AT\R4 command until the modem is power cycled, or restarted
with an AT-R command.

Data forwarding

Data forwarding is the process that causes data sent from the MAS
(remote terminal) to the DART 200 to transmit over the CDPD network.
Data forwarding is operational only in TCP, UDP, and telnet modes.

CAUTION:
If the timer is set to 0,
and a manual
registration (AT\R1) is
tried and fails to
complete, the registration
attempt never times out.
The DART requires a
power cycle to clear this
condition.

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NOTE:
This function was
conceived by the CDPD
specification writers
when it was anticipated
that some carriers would
charge for the time an
M-ES was registered on
the network. However,
since no carriers plan on
charging for registration
time this feature is of
little practical use.

In addition, this option
slows down operations
and generates extra
traffic by requiring
registration protocol to be
executed by the modem
every time a Dial or a
Hang-up command is
issued.

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