In a message dated 10/17/2004 5:38:17 PM Central Standard Time,=20 alainoireaux@club-internet.fr writes:

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Hi LML gang,

does somebody know the answers to those q= uestions=20 ?

1=B0 I would like to install a Trutrak au= topilot on=20 my LNC2.I am seeking informations about the GPSS fonction. Do I need to ha= ve=20 ARINC format signal or is a serial RS 232 signal enough to use the GPSS=20 fonction ? When reading the Trutrak documents it is not clear and=20 Trutrak does not answer to my questions.

2=B0 I have a King KLN 89B GPS in my plan= e . I=20 would like to transmit navigation datas to a KMD 250,as a moving map,and t= o=20 the Trutrak autopilot . If I use the KLN 89B ,P 891 #2 pin (labelled " Gen= eral=20 RS 232 Output") for datas to the KMD 250,can I use the # 6 pin (labelled=20 "Spare RS 232 Out") for nav datas to the A/P ?I asked BendixKing about tha= t=20 problem but I am till waiting for the reply....!

Many thanks for your help and best=20 regards.

Alain NOIREAUX L=20 320

1. Left/Right course deviation. This is the same type of signal t= hat=20 drives the CD indicator and either a VOR, Localizer or GPS may provide such=20= a=20 signal to an A/P circuit that will try to keep the needle centered. Do= es a=20 Tru-Trak interface to a Localizer signal or can it only fly GPS=20 approaches?

2. GPS RS 232 data is usually output in the NMEA Text format and may=20 contain sentences that include Lat/Long, GS, and track deviation=20 information. This information is the type that is interpreted by movin= g=20 map computer programs and some autopilots that may use the track deviation=20 data. Note that this is only present position information. The=20 Tru-Trak understands this as it is the same data produced by the simple Garm= in=20 (35? see Garmin.com) that can used with the Tru-Trak.

3. ARINC data is far more sophicated in its format. Especially si= nce=20 it can send steering data, both horizontally and vertically. The S-Tec= =20 GPSS interface is to take ARINC data and change it into the same autopilot i= nput=20 as that from the DG and the bug on the DG. That is, the GPSS device=20 converts ARINC data and either sends that or the DG information to the autop= ilot=20 based on a switch setting. The ARINC data can be computed by the GPS u= nit=20 to lead a turn (direct future movement) based on your speed and ground=20 track to the turn waypoint. You would need to know if your GPS produce= s=20 the ARINC data, I think that the Tru-Trak can understand it.