Some host computers use Enquire Acknowledge handshaking to prevent the terminal from falling too far behind the host system and losing data.

When the host system has a block of more than 80 characters to send, it sends 80 characters and an ASCII Enq character, and then stops transmitting. When InfoConnect has processed all of the characters preceding the Enquire, it sends an ASCII Acknowledge character, which tells the host that InfoConnect has caught up and is ready for more data.

The default value is false for UNIX and OpenVMS and ReGIS Graphics emulations.

Reference

Terminal Object
Terminal Members