Interfaces; Ttl Interface - DCA Intertel 2000 Technical Manual

3.0 INTERFACES

3.1 TTL Interface

Serial Data Format:
-1 start bit
-8 data bits
-No Parity
-1 stop bit
The transmission rate is selectable within the following values: 1200/2400/4800/9600
Baud.
Baud rate selection is performed by setting dip-switches SW1-1and SW1-2 according
to paragraph 2.5 Most important is to set SW1-3 according to the chosen serial
interface, this being the protocol XON-XOFF (XON = 17dec.= 11hex; XOFF = 19dec =
13hex) or the
DTR-DSR (hardware flag) mode. The TTL level control signals are as follows:
- TxD (output) Transmit Data.
The printer sends data to the computer over this line; when idle, this line is at logic
"1".
- RxD (input) Receive Data.
The printer receives data transmitted from the computer over this line; idle at logic
"1".
- DTR (output) Data Terminal Ready:
"0" = printer is ready to receive data
"1" = printer is busy and cannot receive data.
- DSR (input) Data Set Ready
Controls data exchange from printer to computer
"0" = printer can send data
"1" = printer cannot send data.
NOTE: the terms "input" and "output" refer to the printer.
DCA Intertel 16 DCA Intertel