Measurement Computing Digital232 - Manual (Page 16)

Section 2 Getting Started
2.8
either input or output. At power on, all 40 bits are in the input mode. Each 8 bit
group is one port, beginning with Port 1 as the least significant 8 bits, and Port 5 as
the most significant 8 bits.
2.3.1 Logic Levels
The data and handshake output lines will drive two TTL loads. In addition,
ports 3, 4, and 5 outputs are 5 Volt CMOS compatible. All input lines are less than
1.5 TTL loads. All inputs are protected against damage due to high static voltages.
Normal precautions should be taken to limit the input voltages to -0.3 to +7.0 volts.
All I/O lines are referenced to COMMON (Pin 50).
2.3.2 Digital I/O Port Pinout (rear view)
The following diagram illustrates the digital I/O edge connector as view from
the rear of the Digital232