I thought the RS meter had a line out jack, but I can't find mine so all I have to offer is vague memories and internet gossip... but both of those say "go look, it might have a jack".

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8