The TB4MKIII has been upgraded with a 47 position stepped attenuator made exclusively for Coleman Audio. The TB4MKIII is a control room monitor and communication module all in one. The main signal path is completely passive.with four stereo inputs to A/B signals and two stereo outputs for main and alternate speakers. There's a cue master level control and a switch that selects either the control room signal or a dedicated cue mix. The engineers headphone has a level control and can monitor the control room signal or the dedicated cue mix too.The cue input and outputs are on TRS 1/4" jacks. The talkback switch dims the control room monitors and feeds talkback to the cue mix. There is a slate output (i.e. take 1 take 2) activated by the talkback switch on the back panel just above the remote talkback jack.