Installing and putting a SINAUT modem into operation
6.6 Analog dial-up modem MD3
SINAUT ST7 Station control system - System Manual
System Manual, 05/2007, C79000-G8976-C178-06
291
Note
Any TIM with an RS-232 port can be used, in other words, the TIM 3V-IE variants, the
TIM 4R-IE and all TIM 4 types.
Note
Do not forget to activate the terminating resistor for the RS-485 bus on the last connector
using the slider switch.
RS-485 operation of the MD3
If several MD3s are connected in parallel over the RS-485 port, remember the following
when making the settings for the modem and setting the parameters for the TIM:
1. The MD3 modem must be set to profile 15 using the 10-pin DIL switch.
2. Make sure that this user-configurable profile 15 is set so that it is suitable for RS-485
mode using a PC and terminal program.
3. The RS-485 interface must also be activated at the 4-pin DIL switch accessible from
below.
4. The RS-485 interface of the TIM connected to the MD3 modem must also be activated at
the 8-pin DIL switch accessible from above (applies to all TIM 4 types).
5. Since data traffic can only handled in half duplex over RS-485, the mode of the
connected TIM must be set to half duplex.
6. Once the MD3 has received data and forwarded it to the TIM, the MD3 requires a pause
of several ms before it is ready to send data. The TIM must take this pause into account
by setting an RTS/CTS delay; in other words, after receiving data it must only start
transmitting data after the RTS/CTS delay has expired. The duration of the delay
depends on the transmission speed being used on the dedicated line (see table below).
Table 6-38 RTS/CTS delay for MD3 in RS-485 mode
Speed on the dedicated
line
RTS/CTS delay
Speed on the dedicated
line
RTS/CTS delay
300 bps
100 ms
14400 bps
10 ms
1200 bps
100 ms
19200 bps
10 ms
2400 bps
50 ms
26400 bps
10 ms
9600 bps
25 ms
33600 bps
10 ms