Nortel Passport 4460, Hardware Reference Manual

Page: 146 / 152

146 Appendix C Voice Module Specifications
205677-F Rev 00
FXS Interface Analog Specifications
Crosstalk (Near/Far End)
Between Channels:
<75 dB
Echo Suppression: >35 dB as part of SLAC and DSP settings
Echo Canceling
FXS, FXO, E&M 2-wire:
<16 ms or <1000 Km (600 miles), DSP setting
Signaling
Loop Range
E lead output signaling:
M lead input signaling
<= 900 ohms (or 5000 ft. of 24 AEG wire)
<= 1400 ohms
AC DTMF Signaling (software
settings):
E lead current limit:
To RS-464 standards
<= 30 mA
Signaling Formats (all software
sourced)
DC (2-wire or 4-wire) Steady
Battery and Ring An onboard DC-to-DC power supply that takes +12
VDC outputs from the system supply generates two
supplies: -55 VDC and -25 VDC. These are supplied to
the SLIC which incorporates battery switching on the
chip to maximize power savings. Also, linear voltage
regulators generate the +/-5 VDC needed by the
circuitry from the +/-12 VDC outputs. Another linear
regulator generates 2.5 VDC from +5 V supplied to the
system.
Port impedance Normal 600 ohms
Programmed Complex impedance
Port return loss • 600 ohms impedance >/= 28 dB
• Complex (TBR-21
standard and
Australian standard) >/= 26 dB
• Other unspecified >/= 18 dB