2. Installation
Impedance matching and bias settings
If a specific adjustment is required on the RS485 link, see the settings on DIP switch SA1:
Phone
Settings
JBUS / RS485
OFF
ON
8
1
SA1
◗Master (fixed)
◗
◗Bias
◗Without impedance matching
CD
UPS
A 5V B R+ R- T+ T-
TelPac
Default position
Switch number | Function | Switch number | Function |
|
|
|
|
1 | T+ to R+ connection | 5 | R+ 0V bias |
2 | T- to R- connection | 6 | T- +5V bias |
3 | T+ 0V bias | 7 | T+ T- impedance matching |
4 | R+ R- impedance matching | 8 | R- +5V bias |
|
|
|
|
Example: SA1.6 = ON, T- has a +5V bias,
SA1.6 = OFF, T- does not have a +5V bias.
34003602EN/AB - Page 19
