MC145572PB Freescale Semiconductor, MC145572PB Datasheet - Page 245

• Manufacturer Part Number: MC145572PB
• Manufacturer: Freescale Semiconductor

Specifications of MC145572PB

• Number Of Line Interfaces: 1
• Control Interface: HDLC
• Lead Free Status / Rohs Status: Not Compliant

Freescale Semiconductor, Inc.
On–Hook — The condition when the telephone’s dc path is open, and no dc loop current flows. The central office regards an
on–hook phone as available for ringing.
PABX — Private Automatic Branch Exchange; a customer–owned, switchable telephone system providing internal and/or exter-
nal station–to–station dialing.
Pair — The two associated conductors that form part of a communication channel.
Pass–Band Filter — A filter used in communication systems that allows only the frequencies within a communication channel
to pass, and rejects all frequencies outside the channel.
PBX — Private Branch Exchange; a class of service in standard Bell System terminology that typically provides the same ser-
vice as PABX.
PCM — Pulse Code Modulation; a method of transmitting data in which signals are sampled and converted to digital words that
are then transmitted serially, typically as 8–bit words.
Phase Jitter — Abrupt, spurious variations in an analog line, generally caused by power and communication equipment along
the line that shifts the signal phase relationship back and forth.
PLL — Phase–Locked Loop.
PLL Frequency Synthesizer — Phase–locked loop frequency synthesizer. A frequency synthesizer utilizing a closed loop, as
opposed to DDS (direct digital synthesis) which is not a closed loop.
POTS — Plain Old Telephone Service.
Propagation Delay — The time interval between specified reference points on the input and output voltage waveforms.
Psophometric Weighting — A frequency weighting similar to C–Message weighting that is used as the standard for European
telephone system testing.
PSN — Packet Switched Network.
PSTN — Public Switched Telephone Network.
Pulse Dialer — A device that generates pulse trains corresponding to digits or characters used in impulse or loop–disconnect
dialing.
Quantizing Noise — Signal–correlated noise generally associated with the quantizing error introduced by A/D and D/A conver-
sions in digital transmission systems.
REN — Ringer Equivalence Number; an indication of the impedance, or loading factor, of a telephone bell or ringer circuit. An
REN of 1.0 equals about 8 k . The Bell system typically permits a maximum of 5.0 REN (1.6 k ) on an individual subscriber line.
A minimum REN of 0.2 (40 k ) is required by the Bell system.
Repeater — An amplifier and associated equipment used in a telephone circuit to process a signal and retransmit it.
Repertory Dialer — A dialer that stores a repertory of telephone numbers and dials any one of them automatically on request.
Ring — One of the two wires connecting the central office to a telephone. The name derives from the ring portion of the plugs
used by operators (in older equipment) to make the connection. Ring is traditionally negative with respect to Tip.
RTS — Request To Send; an EIA–232 control signal between a modem and user’s digital equipment that initiates the data trans-
mission sequence on a communication line.
Sampling Rate — The frequency at which the amplitude of an analog signal is gated into a coder circuit. The Nyquist sampling
theorem states that if a band–limited signal is sampled at regular intervals and at a rate equal to or greater than twice the highest
frequency of interest, the sample contains all the information of the original signal. The frequency band of interest in telephony
ranges from 300 to 3400 Hz, so a sampling rate of 8 kHz provides dc to 4000 Hz reproduction.
SCU — Subscriber Channel Unit; the circuitry at a telephone exchange associated with an individual subscriber line or channel.
Sidetone — The sound fed back to the receiver as a result of speaking into the microphone. It is a natural consequence of the
2–to–4 wire conversion system. Sidetone was recognized by Alexander Graham Bell as necessary for a person to be able to
speak properly while using a handset.
Signaling — The transmission of control or status information between switching systems in the form of dedicated bits or chan-
nels of information inserted on trunks with voice data.
Signal–to–Distortion Ratio (S/D) — The ratio of the input signal level to the level of all components that are present when the
input signal (usually a 1.020 kHz sinusoid) is eliminated from the output signal (e.g., by filtering).
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MC145572
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