Uhf Packet Data Operation - Ramsey Electronics FX-440 Manual

UHF PACKET DATA OPERATION
Your FM transceiver was planned and designed to accommodate easy
and reliable UHF packet radio operation.
The J1 Packet 1/0 port can be quickly connected to many modern TNC's
and the Ramsey P-IBM or P64 Packet Modems with Radio Shack's
shielded DIN cable (42-2151). Otherwise, your first step is to prepare a
reliable 5-conductor cable with a 5-pin DIN plug (RS 274-003) at one end,
and the correct connector needed by your packet TNC at the other end.
If you salvage a "ready made" 5-pin DIN cable from something like a
discarded computer joystick, be sure that there are indeed 5 wires, or at
least the ones that are required by your TNC!
Consult your Packet TNC or Packet Modem documentation for ALL
details on hookup and operation. Pin 4 of J1 offers a choice of amplified
and squelched (speaker level) audio output, low-level (discriminator)
output, or FSK output. This choice is set up by the jumper wire positions
clearly visible on the PC board.
Packet RX Audio Jumper: Some TNC's require low-level audio from the
discriminator output of the FM detector, while others will accept speaker
output. Either is available in the FX transceivers. Simply install a jumper
in the appropriate location near VR1, to connect •EXT AU 010" to either
• SPKR" for speaker audio or •DISC" for discriminator audio. Use scrap
resistor wire to make the jumper. You also can choose to wire these
three points to a miniature SPOT switch which you can mount on the rear
panel near the packet connector. OR, use a PC mount switch in the
jumper area itself. Provision is also made for true FSK output (near C7)
from pin 14 of U1, which may be required by some high baud rate
TNC's. Use a short length of hookup wire from FSK to EXT AUDIO.
Use this space to diagram your TNC cable connection:
+12v
PACKET
-
FSK
EXT AUo-Dl_O
-~-+--+--t--t---+--i-<;
~1sc./
_,,,,/JUMPER
-
SP-KR
PACKET JACK
0
0
3 5 2 • 1
FX-440
Ref. 17