Maxon J-STD-008, Руководство пользователя

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PS-SAU-1900E
Mar. 8
th
,1999 (Rev. 0.0)
--- CONFIDENTIAL AND PROPRIETARY ---
15
2.3.2. Electrical Characteristics.
The LIU must conform to the electrical characteristics for analog loop start interfaces defined by EIA-464-
B, except where modified below.
Characteristic Performance Criteria
Tip-Ring AC Impedance (Off Hook)
270 Ω + (750 Ω || 0.15 µ F)
Ring Signal 19 Hz <= f
ring
<= 21 Hz
V
rms
>= 45 V
rms
into 1.75 K Ω impedance on a 1000 ft.
loop.
Ringing Waveform: Trapezoidal signal is acceptable.
1.2 <= Peak / RMS <= 1.6.
Tip to Signal Ground Impedance No requirement.
Ring to Signal Ground Impedance No requirement.
LIU Loop Supply Voltage / Current Idle State: Per EIA-464.
Talk State: Per EIA-464, plus 25 mA < I
sc
< 40 mA for
R
L
< 100 Ω . Also required to drive at least 25 mA into
a standard British Telecom 400
Ω
load.
Ring State: Per EIA-464, plus 100 mA > I
sc
> 70 mA
for R
L
< 100
Ω
.
Maximum Supported Loop Length
100 Ω .
Audio Path Frequency Response 300 - 3300 Hz, +/- 3 dB.
Audio Path Distortion Limits TX: System must accurately decode all DTMF digits
when signals are applied to input at maximum
allowed levels.
RX: Assuming a network signal input level of 3 dBm,
and an internal RX loss plan of 3 dB, output
signal levels must not show clipping over the
range from 300 -3300 Hz.
Loss Plan TX: Total gain in is -4.1 dB, and is comprised of a
hardware gain from Tip/Ring to the CODEC PCM
output after A/D conversion of -4.1 dB and 0 dB
gain in the baseband DSP function, measured at
1 kHz. The PCM bit stream is processed or
generated by a 900
Ω CODEC.
RX: Total gain is programmable from -5 dB to -14 dB
and is comprised of a programmable range of +3
dB to -6 dB in the baseband DSP function
(including vocoder) and a hardware gain from the
CODEC PCM inputs (before D/A conversion) to
Tip/Ring terminated 600
Ω load of -8 dB,
measured at 1 kHz. The PCM bit stream is
processed or generated by a 900
Ω CODEC.
Serial interface Logic “1”:
Logic “0”:
Table 2.3.2.-1: Primary LIU Electrical Characteristics, Where Different from EIA-464.