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Installation Secrets:
GPSS Converter

Butch Nimmo
Tech. Rep.

The introduction of the ST-901 GPSS Converter has been an overwhelming success. From the beginning, though, we have received numerous questions regarding how to set up the GPS receiver to supply the necessary ARINC 429 output.

For most GPS receivers, the parameters listed below are adjustable. For correct operation of the ST-901 GPSS Converter, the following GPS receiver setup should be verified. All of these parameters should be available through the front panel knobs of the GPS receiver while in setup mode.


A few of the most commonly asked questions are:

Q: Do I need to "Turn on" the ARINC 429 output?
A: ARINC out must be switched on

Q: What speed ARINC 429 data does the ST-901 GPSS Converter require?
A: LO speed ARINC output should be selected. (If for some reason your application requires HI speed ARINC, the ST-901 GPSS Converter can accept HI speed. The unit must be opened and strapped for HI speed data in accordance with S-TEC Dwg 0599.)

Q: Will the ST-901 GPSS Converter work with GAMA 429 or Standard 429 data?
A: Select either GAMA 429 or Standard 429 format. The ST-901 will function properly with either. (For applications involving a Sandel SN 3308 HSI, GAMA 429 must be used.)

Hopefully these answers will clear up any issues that might arise during your next ST-901 GPSS Converter installation. As always, please call if you have any additional problems or questions.