Sierra Wireless DART 200 CDPD Modem Dart 200 Cdpd Modem User’s Guide Dart Supported Protocols

DART 200 CDPD Modem User’s Guide 5 DART Supported Protocols

∙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

PN1197-00 Revision 1.0 5-29