The PhidgetEncoder HighSpeed connects to any typical two-bit optical encoder and can return up to 500,000 counts per second. Specifically it reads a standard incremental non-differential TTL encoder.
The 1057 can be used to measure shaft speed or as a very accurate human input device. If you just need a simple human input device have a look at the 1052 PhidgetEncoder.

With it you can:

• Detect changes in incremental position
• Easily track changes with respect to time