AVT MAGIC ISDN, Описание аппаратуры

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PA G E 6 3
ANNEX 3 U S E R I / O I N T E R F A C E A P P L I C A T I O N S
The 25-pole USER I/O interface can be programmed for various different ap-
plications. Three different interface modes are available:
– Command mode
– Logic-level transfer mode
– Printer mode
In the command mode, the USER-I/O interface signals can be used to control
the local codec. The leading and trailing edges of the signal (change of signal
level from “0” to “1” and vice-versa) are evaluated.
In the logic-level transfer mode, the logic levels at the local interface are trans-
mitted to the remote end. This can be used to control external units at the
remote end. For operation with the PC, software can be used to set levels that
are transmitted to the remote end or which are provided at the USER-I/O in-
terface. Here also, the leading and trailing edges of the signal (change of si-
gnal level from “0” to “1” and vice-versa) are evaluated.
In the printer mode, the interface is configured as a Centronics interface. A
printer such as an Epson FX 80 can therefore be connected for log printing
without the need for adaptation.
A3.1 Logic level transfer Mode
To use this operating mode, set the CTRL operating mode in the operator pa-
nel (SYS
→
IFACE
→
CTRL
→
TTL). If you are using a PC to control the sy-
stem, set the TTL-INTERFACE MODE switch to LOGIC LEVEL TRANSFER
(in the TTL-INTERFACE panel).
The logic signals fed in by hardware (pins 10, 11, 12, 13 and 15 at the USER-
I/O interface) are transmitted to the far end and are provided at the outputs
DATA 0 to DATA 4 of the remote USER-I/O interface.
Remark The default levels at the unconnected outputs (pin 10 to
pin 15) correspond to those of a CENTRONICS printer inter-
face:
Pin Pin
10
ACK + 5V
11
BUSY GND
12
PE GND
13
SELECT GND
15
ERROR + 5V