Setra System Model 470 - Manual (Page 6)

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If it does not, (i.e. if the computer also has a DTE interface, and therefore transmits on its own pin
2, and receives on its own pin 3), a “reversing” or “null modem” cable is required for connection.
This is simply a cable which connects pin 2 and 3 of the Setra 470 to pins 3 and 2 of the com-
puter respectively. This kind of cable is commercially available and is also available from Setra.
In addition, some computers which do require handshaking lines will require a connection be-
tween the two pins on the computers connector named DTR and DSR (Data Terminal Reading
and Data Set Ready) in order to enable it to communicate with the 470.
To connect to the Setra 470 RS-232 port:
1. Connect a DB9S (D-Subminiature 9 pin female connector) to a cable from the host with
the following pinout:
6 7 8 9 Pin Description
• • • •
2 TXD - transducer transmits data
• • • • •
3 RXD - transducer receives data
1 2 3 4 5 5 GRD - signal ground
2. Connect the shield of the cable from the host to the threaded standoffs on each side of
the connector shell. Do not use a cable longer than 15 meters.
3. Locate the DB9P communications connector on the Setra 470. It is a
D-Subminiature 9 pin male connector to the left of the pressure port and is marked “Commu-
nications” on the label.
4. Insert the female connector on the host communications cable into the male connector on
the Setra 470 and secure it by tightening the mounting screws on the female connector into
the flanges on the male connector.