HMS Networks Intesis IN701-KNX Series User Manual page 41

Connection to ASCII
• Port B EIA-485 connection for ASCII serial
Connect the EIA-485 bus to connectors B1 (B-), B2 (A+), and B3 (SNGD) to the Port B of the gateway.
IMPORTANT
Respect the polarity.
IMPORTANT
Remember the characteristics of the standard EIA-485 bus:
– Maximum distance of 1200 meters.
– Maximum of 32 devices connected to the bus.
– A termination resistor of 120 Ω is needed at each end of the bus. The gateway has an internal
bus biasing circuit already incorporating the termination resistor. It can be enabled using the
DIP switches:
• Position 1
ON: 120 Ω termination active
OFF: 120 Ω termination inactive
• Position 2-3
ON: Polarization active
OFF: Polarization inactive
– If the termination resistor is enabled and you install the gateway at one of the ends of the bus,
do not install an additional termination resistor at that end.
• Port B EIA-232 for ASCII serial
Connect the serial cable EIA-232 from the external serial device to the EIA-232 connector of the gateway Port
B.
NOTE
This is a DB9 male (DTE) connector that only uses the TX, RX, and GND.
IMPORTANT
Respect the maximum distance of 15 meters.
USER MANUAL Version 1.0
IN701-KNX Series
Page 37 of 44