I found one bilingual ref. 21:20 Nov 20, 2013
but couldn't open it :-(
It suggested 'show relay system' as 'retour audio aux loges' — but that is only really applicable in a quite specific, narrow context: for a start, here we know it is both audio AND video, and also, we have no way of knowing (but it is probably unlikely) that this is going to the dressing rooms: this sort of system is more commonly used to relay the show to FOH staff, or indeed the foyer (for late-comers who cannot be admitted), or else to other technical areas, etc. | 
peer agreement (net): +2