You are such a fine gentleman !!! Thanks !
...so You say to put the entire command in "one place" ?

OutBuffer[0] = ....
to
OutBuffer[n] = ....
and
BitsToSend = n x 8 GOSUB SendBits
?!
I have some doubt about how I understand this :
"You really shouldn't drive the output line at 5V or 3V or any other voltage for a high output. If you want the output to be high, you do that by turning off the PIC's output driver. This way it doesn't matter what voltage the head unit uses, your hardware will always be compatible. It'll work at 5V, 3.3V, or anything.
To do that, search the PIC manual for "Open-drain".
For the 16-bit PIC24F series, you configure the pins as open drain by setting the bits in the ODCx register to '1's BEFORE you configure the pin as an output by writing '0's to the TRISx register."
It's ok what I wrote in code, ie how I use PortC and TrisC ?