User's Manual

XFIN-BLADE-SM
TECHNICAL DESCRIPTION PAGE 33
links F3 and F4 can be fitted to provide bias volts. This allows the unit to use DC
signalling.
4.2.2.8 PSTN Interface
A Clare DAA chip (U7) provides a PSTN interface. An audio channel links the telephone
port to a codec (U54).
At the time of configuration, the audio levels of the PSTN interface should be set for
optimal transmission and reception.
PSTN Interface Specifications:
Isolation
Characteristics
3000 Vrms rated isolation voltage; 2000V/µs rated surge rise time.
Continuous
Output Current
130 mA (max where Rzdc = 8.2Ω).
Ringing Signal
Detect Level
5 Vrms (min for 68Hz applied to tip and ring); 28 Vrms (min for 15Hz
applied across tip and ring).
Frequency
Response
30 to 4000Hz (166Hz to 4000Hz for Snoop Circuit).
Ringer
Equivalence
0.01B REN.
Return Loss
26 dB (typical, into 600Ω at 1800Hz).
Insertion Loss
-0.4dB to 0.4dB (Tx and Rx, 30 to 4000Hz).
Tx/Rx Level
2.2Vp-p (max) for a single-tone sine wave.
4.2.3 Links
For Fuse Links F3 and F4, see E & M above.
Link Remarks
Default
Link Remarks
Default
LN1 In Line 2 M-Wire bias GND -
requires F3 fit
LN11 In Line 2 Two-Wire 600R
Impedance select
Out No bias - barrier is not
breached

Out

LN2 In Line 1 M-Wire bias GND -
requires F3 fit
LN12 In Line 2 UK Complex
Impedance select
Out No bias - barrier is not
breached

Out

LN3 In Line 2 E-Wire +V Bias (input
supply volts) - requires F4 fit
LN13 In Line 2 Four-Wire RX
Impedance Enable

Out No bias - barrier is not
breached

Out Line 2 Two-Wire
LN4 In Line 1 E-Wire +V Bias (input
supply volts) - requires F4 fit
LN14 In Line 2 Complex Imped.
Hybrid Balance
Out No bias - barrier is not
breached

Out

LN5 In Capacitor link for Line 1 UK
Complex Impedance Select
LN15 1 - 2 Line 1 Four-Wire Mode
