IRT Electronics offers TPD-4000 I/O relay modules, eight input / eight input solid state modules that have been engineered to work in conjunction with the 4000 series SNMP frame.
TPD-4000 I/O relay modules are particularly useful for gathering alarm and status information from non-SNMP controlled devices that use either relay or transistor switch to ground output ports, for situations that require SNMP monitoring.
The eight independent inputs on these modules are opto-coupled, and activated by a switch to ground contact. They are then fed into an IRT SNMP module for communication to an SNMP network.
The eight solid state relay outputs have a common connection on one side of their relay. This can be connected to ground or to an external common signal. with the switched side of the output switches either open to circuit or to ground.