I have a couple of uPAC modules from either a Honeywell DDP-516 or just possibly from a H316 machine. They're marked CC690. They're obviously some form of bus termination - just a series of clamp diodes to GND and some lines with pull-ups to +6V. The normal I/O bus termination on a DDP-516 is CC154, and I'm pretty sure that there is no termination uPAC needed on a 316. These were pulled from a machine in about 1984. I have some distant memory that they are an "upgraded" CC154 and can be used in place of a CC154. Can anyone confirm that - either from documentation or just from recollection? Adrian