What type of cable do I use to connect to an AVNs console interface?

It depends upon the AVN model number.

AVN200s, and AVN210s connect using a NULL modem cable (D-Sub 9-Pin for RS-232C). A proper cable is shipped with each of these encoders.

All AVN blades (AVN220, AVN420, AVN422, AVN441 and AVN443) use an RJ-45 (8-Pin) to D-SUB 9-Pin for RS-232C, which are the same as CISCO console cables. Each MPP chassis (MPP200 or MPP1700) ships with one of these cables.