Reliance Automax. In stock ships today! 45C37. 4537. Remote I/O Interface. Input/Output module. The Remote I/O Interface (or remote I/O head) is used in conjunction with I/O rails and digital I/O modules to create a digital I/O subsystem. A maximum of four I/O rails can be connected to a remote head for up to 64 digital I/O, or a maximum of four local heads can be connected if up to 256 digital I/O are required. The remote head receives data from the remote I/O processor in the master rack, updates the modules, the I/O rails, and then transmits the data back to the master. The remote head also includes a power supply capable of supplying power to four full ports of digital I/O modules. 45C37 for 120/240 VAC operation.