AP-16+ not responding to servial commands

[phalon]

I am connecting a Prop1 to an AP-16+. I'm using a 3 pin cable from p7 to the serial connector on the AP-16+. When I run my code with this

Symbols definition for code

Code Select Expand

' -----[ I/O Definitions ]-------------------------------------------------

SYMBOL  Sio             = 7
SYMBOL  Baud            = OT2400                ' baud jumper out
SYMBOL  Yes             = 1
SYMBOL  No              = 0
SYMBOL  status          = B0                    ' status (B0 for bit access)
SYMBOL   Playing        = BIT7                  ' 0 = idle, 1 = playing

SYMBOL  id0             = B2
SYMBOL  id1             = B3
SYMBOL  id2             = B4
code:

Code Select Expand

  SEROUT Sio, Baud, ("!AP16", %00, "V")         ' get version
  SERIN  Sio, Baud, id0, id1, id2               ' receive ID string

Switches on the AP-16+ all off except the repeat switch
The program will pause here until I disconnect the cable. I have an ambient file, which plays and an SFX00 file which plays when I press the start button.

what is causing the AP-16+ not to respond or the prop1 to not send the signal properly?

Edit: Is there a way I can determine if the Prop1 isn't sending out commands to the AP-16+ properly?

[JonnyMac]

The usual cause for errors are:

-- ULN influence on P7 (replace with ULN2003 or clip pin 1 of ULN2803)
-- P7 SETUP jumper in the DN position
-- bad cable connection
-- broken cable