I/O Telemetry systems transmit analog or digital signals and replicate them exactly at another site. For instance, a 4-20mA loop current at the input of the Telemetry system at one site is reproduced as a 4-20mA loop current at the Telemetry system output at the other site.

I/O telemetry can be:

• ●  unidirectional or bidirectional
• ●  point-to-point or point- to-multipoint
• ●  digital, analog or both
• ●  wireline or wireless

Reasons for Using I/O Telemetry:

• ●  remote I/O is required at a local hardware I/O interface
• ●  I/O Telemetry is a more cost effective solution than PLC's and RTU's when the amount of I/O involved is very low.

Below is an illustration of a typical Wireless End-to-End I/O Telemetry system using SCADALink 900-MB's. Here the Telemetry link is bidirectional; inputs/outputs on one side map respectively to outputs/inputs on the other side.