User connections are made to a standard screw terminal strip. The rigid wiring system permits module insertion or removal without disturbing the wiring.

Pull-up resistors must be installed at the active device end to use the B864 output module. The value of the pull-up resistor depends upon the number of devices that are attached to the data bus, as explained below. Each output meets 0.4 V maximum at 16 mA for a logic low and 3.3 V minimum at 16 mA for a logic high. If the current limit has been exceeded, the pull-up resistor values should be adjusted within specification; otherwise, spurious results may be obtained.

The following illustration indicates how the resistors are connected at the device end. For a single device consisting of 16 data lines, 16 1 K resistors are required, or, one 1 K resistor/data line. As additional devices are added to the data bus, the value of the pull-up resistor must be increased by 1 K. In other words, if two devices are used, the pull-up resistor must be 2 K, three devices require a 3 K pull-up, and so on, with the maximum number of 8 devices requiring 8 k of pull-up for each data line.