DESCRIPTION AND OPERATION
TIMING INTERVAL
I-E96-624A
2 - 3
of modems and transmission equipment. The interface coordi-
nates this activity through the RTS (Request-To-Send) signal of
the RS-232-C port for modems or through digital outputs when
using Digital Slave Modules (IMDSM05, IMDSO01/02/03/04)
to enable other transmission equipment.
Transmit/Receive Timing
The user can set up the RS-232-C ports to operate as Data Cir-
cuit-Terminating Equipment (DCE) or Data Terminal Equip-
ment (DTE). In the DCE mode, the Request-To-Send (RTS) line
is always asserted. In the DTE mode, the RTS line is asserted
before data transmission and inhibited after data transmission
occurs.
The following events occur (see Figure
) on port 0 when
transmitting a command:
1. Assert RTS on the RS-232-C port (DTE mode) or set digital
outputs 1 and 4 on the digital slave module.
2. A delay occurs between the time the port 0 asserts the RTS
(or the digital outputs are set) and the command transmission
occurs. Function Code 130 (S5) sets this delay (in
milliseconds).
3. Output 4 is reset.
4. A delay occurs between the time output 4 is reset and out-
put 1 is reset. Function Code 130 (S6) sets the length of this
delay.
5. Output 1 is reset and RS-232-C RTS signal is inhibited
(DTE mode).
6. A delay set by S5 of Function Code 130 occur between the
output 1 reset and the reception of the reply.
7. The remote target issues a reply.
The following events occur (see Figure 2-1) when Port 0
receives a command:
1. The port receives the command.
2. A time delay set by S6 of Function Code 130 occurs.
3. The RS-232-C asserts the RTS signal (DTE mode) or set
outputs 1 and 4 on the digital slave modules.
4. A time delay set by S5 of Function Code 130 occurs.
