Here's what looks like their writeup on the connection protocol:
> "We consider the use of ARQ methods on the downlink channel of deep-space missions. Some rudimentary forms of ARQ are already used in deep-space missions, where blocks of corrupted or lost data are isolated and requested again from the spacecraft. Retransmission methods have been considered, particularly as a playback strategy to overcome weather outages. We propose to use retransmission methods in a more systematic and automatic fashion... We consider an interplanetary spacecraft transmitting frames of data to Earth."
> "We consider the use of ARQ methods on the downlink channel of deep-space missions. Some rudimentary forms of ARQ are already used in deep-space missions, where blocks of corrupted or lost data are isolated and requested again from the spacecraft. Retransmission methods have been considered, particularly as a playback strategy to overcome weather outages. We propose to use retransmission methods in a more systematic and automatic fashion... We consider an interplanetary spacecraft transmitting frames of data to Earth."
https://tmo.jpl.nasa.gov/progress_report/42-122/122L.pdf