Redundancy Adds Reliability To 4-Channel A/B Switch

With dual serial remote-control ports and dual power-supply ports, the Electro Standards Laboratories Model 7283 4-channel RS530 A/B switch with DB25 interface (see the Figure) offers redundancy that ensures high reliability. Two separate external power supplies are connected to the unit. Internal circuitry automatically regulates which supply will power the unit. If a supply is removed, the supply remaining will power the unit.

Remote access is accomplished by RS-232 commands sent via the remote serial ports. To increase reliability, all switched signals are passed via copper contact relays that maintain their position and continuity even in the event of a power loss or failure. Remote commands include changing and querying the switch position and locking and unlocking the front-panel pushbutton control. All 25 signal lines of the DB25 RS530 interface connectors are supported.