11-15 
 
3.2  JLN-900 Proprietary Messages 
JLN-900 has been allocated the proprietary mnemonic "SAL" by NMEA. This means that any 
message starting with "$PSAL..." emanates from JRC equipment and that any letters 
following can be chosen by us. However, to comply with standard NMEA messages, all these 
messages uses a five-character combination $PSAL- before the first delimiter. 
 
These proprietary messages are mainly used for internal programming, trouble-shooting, etc 
and are only used in normal operation where no good alternatives are available. 
These messages may be changed without notice. 
3.2.1  Log control messages (PSALC) 
3.2.1.1
 Log control message 2: Bottom track transmit control 
 1     2 3 4 
$PSALC,2,i*hh<CR><LF> 
Field #  Field Type  Definition  Note 
1 
Name 
Proprietary SAL Control  PSALC 
2 
i. 
Control message type  2: SAL T2 BT control 
3 
i. 
Bottom track transmission  0: Set transmit mode off 
1: Set transmit mode on 
4 
hh 
Check sum   
Example: Force acoustic transmitter off: 
$PSALC,2,0* 
 
3.2.1.2
 Unit control message 3 (transmit status) 
This message is intended for switching NMEA message transmission on or off. The primary 
use is to switch off units when information is not needed by sending transmit status "Silent", 
and to reactivate by sending "Active".  
 1     2 3 4 
$PSALC,3,c*hh<CR><LF> 
Field #  Field Type  Definition  Note 
1 
Name 
Serial control message  PSALC 
2 
i. 
Control message type  3: Transmit status 
3 
c 
Transmission status  'A'=Active, 'S'=Silent 
4 
hh 
Checksum   
Example: Turn off NMEA transmission: 
$PSALC,3,S*