Description Of The Physical Interface; General; Handshaking Protocols - Tally T5023+ Programming Manual

Appendix

Description of the physical interface

The physical interface of the document printer makes serial asynchronous data
transmission possible. Optional the document printer can be retrofit with an Cen-
tronics interface.
The following sections lists the performance characteristics of the interfaces.

General

The document printer comes standard with a serial asynchronous interface.
You can control data transmission with the XON / XOFF protocol and the hard-
ware handshaking DTR.
Optionally, a secondary serial interface, a Centronics card, a Ethernet card or a
B-Loop card can be installed in the document printer.
Parameters for the active interface are defined in more detail in a menu.

Handshaking protocols

Data transmission between the host and the printer is controlled by the hand-
shaking protocol.
Hardware Handshake via the DTR Signal
In the DTR/Busy protocol the printer signals by the activated signals DTR and
RTS its readiness to receive data to the connected device.
DTR and RTS are activated:
1.
When the printer has been switched on (power on).
2.
When the status changes from STOP to ONLINE.
3.
When the available input buffer area of the printer accept new data (at
least 1 kByte free input buffer) after having been disabled (less than 512
Byte free input buffer).
Description of the physical interface
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