Page 40 of 101
DWG ID: 181-0101-00A
Date: 2003-09-26
If CONMODE = TRANS
Use the transparent data escape sequence, i.e.; send a series of three control-Cs (unless a
different control character has been defined). (See TRANS command in the Reference
Manual).
9.6
Line Substitution (LINE SUB) Mode
9.6.1
LINE SUB Mode Protocol Description
The LSUB mode of operation provides a method of transmitting-and receiving raw
ASCII data via a radio. Data is sent and received in a totally transparent fashion, allowing
all ASCII characters to be utilized (hex 00 through hex FF). There is no addressing, error-
detection or automatic retransmission of the data. When the receiving modem detects the
proper Start-of-Data sequence generated by the transmitting modem, it will output the
data that follows to its serial port. At the end of the received data there is an End-of-Data
sequence that permits the receiving modem to recognize the end of the data and quit
translating. Since the protocol constitutes a very small portion of the transmission, the
effective data throughput is very nearly that of the radio bit rate.
9.6.2
LSUB Mode Operation
9.6.2.1
Commands Used
PACTIME - The PACTIME parameter determines how long the modem will wait after
receiving data to be transmitted from the DTE before beginning the radio key-up
sequence. Normally, this parameter should be set to AFTER 1 (100 ms.) in order to
minimize "dead-air" time on the system.
PERSIST and SLOTTIME - These parameters determine how aggressively the modem
will attempt to access a multi-user channel based on carrier detect. See KPC-series
manual for a full explanation of these parameters.
9.6.2.2
Entering LSUB Mode
When you have made any desired changes from the default settings for the above
parameters, use the INTFACE command to begin LSUB operation. Set the INTFACE
command to LINESUB:
cmd:INTFACE LINESUB <cr>
and turn the unit off and then back on. Be aware that there is
no
data flow control.
9.6.2.3
Exiting LSUB Mode