[Packet] Icom V8000 for packet

[Haring family]

How should the Icom V8000 wired for packet?  I see the pin-out in the manual, and the CBL-45 pin-out from BuxComm, but I don't see any reference to use of pin 8 labeled Data IN on page 2 of the Icom manual.  Seems a shame to have a pin for data in with no instructions!  I'm initially wanting to connect this to my Pocket Packet (HW-21) through the modular jack, and make up the wire myself.

Thanks in advance!

Dave KL7P