User manual

NurseCall Main Unit Installation | en 33
TeleAlarm SA® User Manual 953.92 | v1.0 | 2007.07
6.2.8 Connecting the RS-485
One NurseCall Main Unit and up to 32 NurseCall Relay Units can be connected to a RS485-bus.
Please contact a specialist for correct installation.
X See Section 13.7.4 RS-485 (unit rear), page 87 for connector wiring.
Fig. 6.8 Right connection
Fig. 6.9 Wrong connection
!
CAUTION!
Do not use a star connection for the RS-485 network !
i
NOTICE!
The NurseCall Main or Relay Units located at the two ends of the bus must be terminated with
a 100 Ohm resistor.
X See Section 6.2.9 Setting the 100 Ohm termination jumper, page 34.
V
T
eleA
la
rm
®
N
u
rseC
a
ll
V
T
ele
A
la
rm
®
N
urseC
a
ll
Main Unit
Relay Unit 1
V
T
e
le
A
la
rm
®
N
urseC
a
ll
Relay Unit 2
RS 485 bus (1 twisted pair cable)
V
T
eleA
la
rm
®
N
u
rseC
a
ll
Relay Unit n
100 100
Main Unit
Relay Unit 1
Relay Unit 2
V
T
e
le
A
la
rm
®
N
u
rseC
a
ll
N
u
rs
eC
all
V
T
eleA
larm
®
N
u
rs
eC
a
ll
V
Relay Unit n
Main
N
u
rs
N
u
rs
eC
all
Relay Uni