GPS Receiver and SPAN SDLC card synchronization

There are two LED lights on the SPAN SDLC card. There is one green light and one red light. The meaning of SDLC LED lights in startup: - Starts with green on. - If it doesn't detect GPS receiver on 232 or 422 then it cycles between 232 and 422 and light should be orange. - When receiver detected, turns both green and red LEDs off. Different Scenarios:

1) Solid orange - It means there was never any communication between the SDLC card and receiver.

2) Solid red - then communication lost between SDLC card and receiver. Also there is no communication between IMU and SDLC card.

3) Solid red and Blinking Green - communication lost between SDLC card and receiver. The IMU and SDLC card are still talking.

4) Blinking Green - Everything is as it should be. The receiver and SPAN SDLC card normally establish communication right on power up. There are four cases here regarding the synchronization:

Case 1) If both receiver and the SDLC card have been power-cycled, which means the SDLC card needs to re-synchronize with the GPS receiver. If the receiver and SDLC card both get powered up at the same time, then the SDLC will have to wait until the GPS receiver has achieved FINESTEERING time to start the synchronization. On the SDLC card, you will see Solid green -> orange for some time -> then when the receiver has achieved FINESTEERING, the led on the SDLC card will change to blinking green.

Case 2) Both receiver and the SDLC card have been power-cycled. If the receiver gets powered up slightly before the SDLC card gets powered up, then the SDLC will recognize the RS232 port from the receiver and will have to wait until the GPS receiver has achieved FINESTEERING time to finish the synchronization. On the SDLC card, you will see Solid green -> then when the receiver has achieved FINESTEERING, the led on the SDLC card will change to blinking green.

Case 3) After the receiver and SDLC card have been synchronized and only the SDLC card was power-cycled. On the SDLC card, you will see Solid green on start up -> then when detected the receiver has achieved FINESTEERING, the led on the SDLC card will change to blinking green. Case 4) After the receiver and SDLC card have been synchronized and only the receiver was power-cycled. On the SDLC card, you will see blinking red and orange since communication between receiver and SDLC card has been lost -> then when the receiver is powered up, the led on the SDLC card will change to blinking green.