Filter
Top Products
133
Chapter 3. Communications Operations of the BHT
[ 2 ] Control Characters
The control characters are classified into two groups: transmission control characters
and text control characters.
(1) Transmission control characters
The transmission control characters listed below are used to compose transmission
control sequences in phases 1 through 3.
Symbol Value Meaning Function
EOT 04h End Of Transmission Releases a data link (Phase 3).
Requests abort of transmission
(Phase 2).
ENQ 05h Enquiry Requests establishment of a data link
(Phase 1).
Prompts the receiver to respond to
the sent text (Phase 2).
ACK 06h Acknowledge Acknowledgment response to ENQ
(Phase 1).
Acknowledgment response to text
(Phase 2).
Acknowledgment response to EOT
(Phase 3).
NAK 15h Negative Acknowledge Negative acknowledgment response
to ENQ (Phase 1).
Negative acknowledgment response
to text (Phase 2).
■ Transparency
The BHT uses the non-transparent mode which handles the control characters and
codes (e.g., STX, ETX, and SOH) as starting or ending markers and does not allow
them to be transmitted as normal data in the transmission texts.