The HHB Portadisc comes with a 'remote' socket, already for transport controls to be implemented in any form you like.
The HHB Portadisc has a rather useful pause after track function, so that I can keep pressing pause to cue the next track.
Step 1: The HHB Portadisc
I bought this specifically for my puppet shows and to record audio for some animated stores I was working on at the time.
You can see in the second picture the socket labelled 'remote'. This is where the remote plugs in.
Step 2: Pin out and circuit diagram
When I plugged my remote into the Portadisc the first time, the Portadisc was off. I assumed that the remote on was a remote means of powering up the port a disk.
!! WRONG !!
The remote on simply enables or disables the switches on the remote. Like I say, it took far too long to work that out!!