Sierra Wireless DART 200 CDPD Modem - Manual (Page 103)

DART 200 CDPD Modem User’s Guide 8 Application Programming
PN1197-00 Revision 1.0 8-9
Manual transmit control
This feature (AT\Mn) controls the recognition of data forwarding
characters in the data stream by the packet assembler when in online
mode. If enabled, the DART 200 recognizes the receipt of either of two
data forwarding characters from the MAS as a condition to transmit the
data in the packet buffer. Any data following the data forwarding
character is not included in the current data packet, but is held over for
the next transmission.
The \Fn command specifies whether or not either, or both, of the data
forwarding characters are included in the data packet. These characters
are specified in S-Registers 51 and 52. The default value for S-Register
51 is 13 <
CR >, and for S-Register 52 is 26 < SUB >; these values can be
changed by the end-user. The default for \Fn is \F3; include both
characters in the packet.
If manual transmit control is disabled, the data forwarding characters are
included in the data packet regardless of the setting of the \Fn command.
The DART 200 factory default is Manual Transmit Control disabled
(\M0).
Automatic transmit control
This feature controls the use of the inter-character time-out data
forwarding operation of the packet assembler when in online mode. The
inter-character timer determines the amount of time (idle time) allowed
between characters received from the MAS. The time out value is
specified in S-Register 50 in 1/10 second increments; the default value is
20 (2 seconds). For optimum performance set this value as small as
possible, values of 1 (100 ms) or 2 (200 ms) are commonly used
The time-out period can be viewed as either the maximum time
permitted between two characters for them to appear in the same packet,
or the wait time after the last character is put in the buffer until the
packet is transmitted. Automatic transmit control must be used with
binary data since it is not dependent on data stream content.
This feature is controlled by the AT\Tn command. The DART 200
factory default is Automatic Transmit Control enabled (\T1).
CAUTION:
Automatic transmit
control must be used
with binary data since it
is not dependent on
data stream content.