4 Camera B/W Multiplexers 
ATV TALON 4M 4 Camera B/W Triplex Multiplexer TALON4M

TALON4M Specs:

Full Triplex operation

1 Main Monitor output

4 Call Monitor outputs

Simultaneous multi and full screen viewing

Motion Detection has programmable 256-cell grid for each screen

Vector Based Motion Detection

Can play back most manufacturers tapes

Camera inputs are Auto-Terminated

Composite and S-Video VCR connections

Many more features