The system was Automatic Airborne Radio Relay (AARR), commonly known as "Autocat" All the tankers I flew (Victor and VC10) had it fitted and it was a secondary role for the fleet. I only did one of those sorties on a Victor during a JMC exercise. Bloody boring!
IIRC one of the major problems was that the automatic system meant tying the radios together so they couldn't be used by the crew. The aircraft only had two VHF/UHF sets to that meant they couldn't talk to ATC or ADGE, and for radio relay they orbited above FL245.
Which meant that the usual means of operation was voice relay by the crew so they could share the comms. Tried it a couple of times attempting to use HF for control, but it proved far to slow and patchy.