The t.racks DS 2/4 User Manual page 17

11 Plug for mains cable with fuse holder.
12 RS232 interface, 9-pin D-SUB socket.
13 OUTPUTS
Signal output 4 to 1 (male XLR panel connector).
14 INPUTS
Signal input channel A and B (female XLR panel connector).
DS 2/4
Connectors and controls
17