Link Control Records (LS / LA / LE / LD / LR)

After every connect, the third-party system must complete the handshake — identify itself, declare which records and fields it needs, then keep the link alive. An incomplete handshake is the most common cause of “connected but no data”.

Typical handshake

3rd party → OPERA   LS|DA261020|TI093000|
3rd party → OPERA   LD|DA261020|TI093000|V#1.0|IF..|
3rd party → OPERA   LR|RIGI|FLRNG#GNGAGD|
3rd party → OPERA   LR|RIGO|FLRNG#|
3rd party → OPERA   LA|DA261020|TI093000|
OPERA → 3rd party   LS / LA ...

STX/ETX omitted. IF is the interface type code — see the specification for values.

Record	Common fields	Meaning
LS / LA / LE	`DA` `TI`	date, time
LD	`DA` `TI` `V#` `IF`	date, time, third-party version, interface type
LR	`RI` `FL`	`RI` record type wanted; `FL` concatenated field IDs

Tips

Send one LR per record type you want.
Treat a long silence (no LA) as a disconnect and reconnect.
Repeat the full handshake after every reconnect, and resync if needed.

Last reviewed：2026-10