Most of you probably know this already but for the few like me who didn't, read on.

The ability for one device in our cockpits to talk to another(humans excluded), is generally through serial data ports with each data port
having Tx and Rx capability. So at least in the case of older Apollo/UPS/Garmin products, device A can transmit data to multiple receivers, up to 4 I think.
But device A can only receive data from 1 external source. I had wired the MVP-50 to send fuel flow data to the GX60. At the same time the GX60 was
receiving data at the same port, from another source, namely the SL30. Not good. The data from the SL30 wasn't needed anyway so the simple solution was to snip and secure one wire. So a word to the wise, read the fine print! I can only begin to imagine the aggravation of chasing down this problem with the plane all buttoned up.

Angier Ames
N4ZQ