2
Characteristics of the Parallel link
2-1 Signals transmitted by the Parallel link
8 data input signals (D0 to D7) which enable the selection of the number of the message to be
printed.
1 input singal, called "DTOP", which enables the validation of the active message number in
the memory and starting-up of printing.
1 output signal, called "BUSY", which indicates that printing has started.
NOTE:
The input/output signals being photocoupled on the Industrial
Interface card each require an electrical reference wire (see Chapter
3 of present Section).
2-2 Characteristics of transmitted levels
The active level (logic 1) is comprised between 9 and 24 volts D.C.
The inactive level (logic 0) is comprised between 0 and 2 volts D.C. (see Figure 1).
The current admissible on input is comprised between 9mA and 25mA.
The input frequency must not exceed 10 Khz.
Figure 1 :
Authorised logic level
1
– – – – – – – – Active level (logic 1)
2
– – – – – – – – Anactive level (logic 0)
2
1
9 V
2 V
0 V
24 V
Status to be forbidden
Figure 1
Parallel link - Presentation
A13862 Version E
Page 7-3
