Siemens SINAUT ST7 - With RS485 Interface Operating Mode

Operating Modes and Character Recognition
© Siemens AG 2002 All Rights Reserved 6NH7811-0AA22
MD2 Modem (07/2002)
4-7
4.1.4 "With RS485 Interface" Operating Mode
The operating mode "With RS485 interface" must be set when the DTE is
connected to the MD2 modem via the RS485 interface. In this case the RS232
interface of the modem is switched to passive.
Any number of MD2 modems can be connected with each other via the RS485
interface because the RS485 interface is multi-point capable. It is therefore
possible to build a star network. A point-to-point connection or a multidrop network
can be connected to each modem.
The "With RS485 interface" operating mode can only be used with the transmission
type "2-wire half-duplex" but with all available character recognition methods
except for "MID off" (see Table 4-1).
Note
Note that the message running time is increased by 13 bits for each RS485 bus
segment.
Note
The minimum message intervals must be adhered to (more information about this
is available in section 4.2).
The following illustration shows the setting on the 10-pin DIL switch of the MD2 for
the "With RS485 interface" operating mode.
Fig. 4-4 DIL switch setting for the
"With RS485 interface" operating mode
123 4
OFF
ON
5678 910