These are the parts contained in the LC485-1 Kit.  Two of these boards are required when using US Digital Incremental Encoders.  They are used to convert the TTL signals from the encoders to RS-485 levels for transmission to the CT-1 controller.  At the controller another board is used to convert the RS-485 signals back to TTL level.  The schematic is shown below.

Using RS-485 level signals on the line between the encoders and the controller board is necessary to reduce susceptibility to noise and RF fields.

A wire jumper must be installed between the pads W12 and either W11 or W13, to configure the board to be at the encoder, or at the controller end of the line.

When connecting the encoder data lines to the board, you connect data A to Pad3 and Data B to Pad5.  Reverse if the direction needs to be reversed.

Data Connector for AZ or
EL encoder connection
Pad 1 Ground
Pad 3 Data A or B
Pad 4 + 5 volts to encoder
Pad 5 Data B or A