Agilent / HP / Keysight 44474A

This digital I/O module provides 16 bi-directional data lines (bits) plus 4 lines used for control and handshaking.

All lines are TTL compatible.

The 16 data lines offer TTL compatible input and open collector output.

The 16 I/O lines or bits can be addressed individually (bit-by-bit), or as two independent 8 bit ports, or as one 16-bit word.

For instance, one port can be used for output operation, while the other for input.

Each I/O line can sink current up to 0.125A from external devices.