Sierra Wireless DART 200, User Manual

Page: 83 / 206

DART 200 CDPD Modem User’s Guide 5 DART Supported Protocols
PN1197-00 Revision 1.0 5-29
•
Data Forwarding Operation
•
Manual Transmit Control ( AT\Mn ) - Controls the use of the
characters (specified in S-Registers 51 and 52) for data
forwarding while in online mode. The default for this parameter
is \M0 (disabled). The default for S-Register 51 is
<
CR
>, that
takes effect only if manual transmit control is enabled.
•
Automatic Transmit Control ( AT\Tn ) - Controls the use of the
inter-character time-out period (specified in S-Register 50) for
data forwarding when in online mode. The default for this
parameter is
\T1 (enabled)
With the defaults listed above in effect, characters are
transmitted to the telnet host process (remote login or gopher)
and echoed back from the remote system for display as they are
entered. This generates a lot more packets, but ensures an
accurate display of the data as seen by the host application.
If your telnet host process operates correctly with, or requires
block mode data transfers (a string of characters followed by a
<
CR
>
), then set local echo ( F0 ), manual transmit mode enabled
(
\M1, and disable inter character data forwarding ( \T0 ). A local
echo is recommended, in this case, so you can view keys as you
enter them without pressing the
<
CR
> key.
•
Telnet Keep-Alive - Allows the DART 200 to keep a telnet
session alive (not time out) if the terminal user has excessive
think time between entries. Without this capability the telnet
session could be terminated prematurely by the server
This facility can work in transmit mode, receive mode, or both. It
uses a non-intrusive telnet NOP command packet and a
keep-alive time-out value (S-Register 86) to implement the
function. The keep-alive timer restarts when data is sent or
received regardless of the mode selected (transmit, receive, or
both).
If the timer expires with the transmit option specified, pending
data or the telnet NOP command is forwarded. If the NOP
(keep-alive) is sent the telnet server protocol ignores it, but the
session is not allowed to time out. This is the normal use of the
function.
If the timer expires with the receive option specified, an ATH
command is issued to close the connection.
The default for this function is *T0 (not enabled). Refer to the
*T command in Appendix F, DART AT Command Set, for details
on how to use this command.
•
Linefeed after
<
CR
>
- S-Register 1 controls whether or not a linefeed
( <
LF
> ) is sent with a carriage return (
<
CR
>
), for telnet mode only.
The default is 1 (send <
LF
>
with <
CR
>
). When not enabled, a NULL
character follows the
<
CR
>
as specified by telnet protocol