The Relay Box is a small box (150 mm x 85 mm x 20 mm) containing 4 relays each one driven by photocoupler.

The unit is mainly designed whenever multiple equipment (such as satellite receivers driving hard disk recorders, mixing consoles driving OnAir warning lamps, etc) need to be electrically decoupled, wherever TTL commands need to be transformed into clean contact closures and in many other applications.

For greater versatility, the same box can perform, depending on the internal jumper settings, 2 FlipFlop stages (with Set/Clear commands each) driving two relays in addition to direct control of relays from photocouplers.

6 Leds on the top surface show presence of power rails and relay status. The Relay box requires standard + 5Vdc voltage (power is generally coming from GPI/O cards in the computers). For easiest installation, in addition to male/female DB25 connectors, the Relay Box features also a DB9 male connector on the top, which groups a selection of the most used I/O contacts.