If you have a VCR with FiOS. The connection is as follows coax from Verizon network to RF in on set top box the RF out from cable box to the RF in on VCR and the RF out on VCR to the RF in on the Television set. To record you must tune your VCR to channel 3 ONLY and tune the set top box channel to the one you would like to record. The television should be set for channel 3 also.
Personally, I would not use the RF OUTPUT since it won't give you stereo audio and you are dealing with multiple modulation / demodulation. I would use the line input of the VCR with composite video and the L-R RCA audio.
The answer the OP was looking for is that Verizon is either all digital or going to be within the next couple of months (depending on where you live)