4RF Aprisa XE User Manual page 117

7. Select the DFXS Line Impedance
This option sets the DFXS line termination impedance and the hybrid balance impedance to the same
value.
Selection
600 Ω
600 Ω + 2.16 uF
900 Ω
900 Ω + 2.16 uF
TN12
TBR21
BT3
On a short line (< 100 meters), the selected impedance should match the impedance of the phone
(off-hook).
On a long line (> 1000 meters), the selected impedance should match the impedance of the phone
(off-hook) as seen through the line.
If you are not sure what the expected impedance value should be, check with the CPE equipment
supplier.
8. Set the DFXS Transhybrid Balance (usually not required to change).
The default Transhybrid Balance value (0 dB), provides the best circuit performance where the
balance impedance (set by the Line Impedance setting) matches the impedance of the line.
You should only adjust the transhybrid balance when the balance impedance does not match the
actual line impedance. You can achieve small circuit improvements using this option.
9. Set the DFXS Ringer Frequency.
This option sets the DFXS Ringing Frequency.
Selection
17 Hz
25 Hz
50 Hz
Description
Standard equipment impedance
Standard equipment impedance with low frequency
roll-off
Typically used on loaded cable pairs
Typically used on loaded cable pairs with low
frequency roll-off
Standard complex impedance for Australia
Widely deployed complex impedance
Standard complex impedance for New Zealand
Description
Used in older networks
Standard ringing frequency
Used by some telephone exchanges
Aprisa XE User Manual
Configuring the Traffic Interfaces | 115
Default
Default