USB interface module SEI-USB

The SEI-USB is an interface module that connects US Digital's SEI compatible devices to a standard USB 1.1 / 2.0 port. The SEI (Serial Encoder Interface) bus is a network that connects up to 15 addressable SEI devices using a single 6-wire telephone-type cable up to 1000 feet long. The SEI bus uses two differential signalling pairs, one for busy flow control, and the other for bi-directional serial data (see the SEI data sheet). The SEI-USB will supply power from the USB port to a number of SEI devices on the bus (for example, five A2 encoders at a distance of 250 feet). The SEI-USB limits the power to the maximum design spec of the USB port. A red LED, next to the SEI connector, will be lit when additional power is required and the PS-12 power supply should then be used. A green LED, next to the USB connector, is lit when the USB connection is established with the host.