Maximum Number of Serial Tx Splits

flickroll · #1 03-14-2010, 06:34 PM

I'm wiring up an AFS system that will include a G430W. The 430 Aviation serial out goes to AFS and the TT AP head. I would also like to send it to a G696, which would be a total of 3 devices being fed by 1 serial output. Is this OK? Thanks

Sparky · #2 03-14-2010, 08:24 PM

Most off-the-shelf RS-232 serial transmitter chips can handle 4 or 5 connections without any problems. I'm not sure what Garmin uses, but I'm pretty sure you'll be OK with 3 connections. I would recommend contacting Garmin to be sure.

skylor · #3 03-14-2010, 10:18 PM

Quote:

Originally Posted by flickroll

I'm wiring up an AFS system that will include a G430W. The 430 Aviation serial out goes to AFS and the TT AP head. I would also like to send it to a G696, which would be a total of 3 devices being fed by 1 serial output. Is this OK? Thanks

If I recall correctly, my 430 manual states that each serial output can drive a maximum of 4 serial devices. I don't have the manual handy at the moment to verify this.

Skylor

Ironflight · #4 03-15-2010, 10:22 AM

I'm driving three from one, so I can tell you that works. The trick, of course, is finding a format that all three of the "receivers" like, and that the "sender" can transmit....

az_gila · #5 03-15-2010, 01:20 PM

...so as long as all of the feeds are behind the panel, you should be OK. You aren't feeding anything in the wings or tailcone are you?

RS-232 will drive a single load up to 25 ft or so, more loads will reduce this distance.

Garmin's 430 spec only seems to give a load number for the ARINC lines - they just state that their RS-232 drive meets the EIA specification.

roee · #6 03-15-2010, 01:37 PM

Yep, if all the endpoints are a short distance apart, it'll probably work fine. If a long distance away, then reflections become an issue and you might have problems. If you did have receivers a long distance away, then you could make it work by splitting to individual repeaters near the transmitter, and then a long point-to-point connection from repeater to receiver. This is just FYI. Since it sounds like all your devices are right there in the panel, it'll probably work just fine as-is.