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參數(shù)資料
| 型號： | MH88634B |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | Central Office Interface Circuit(用于中央辦公電話線的接口電路（在音頻轉(zhuǎn)換設備和用戶線之間提供一個模擬和信號連接）) |
| 中文描述： | 中央辦公室接口電路（用于中央辦公電話線的接口電路（在音頻轉(zhuǎn)換設備和用戶線之間提供一個模擬和信號連接）） |
| 文件頁數(shù)： | 3/13頁 |
| 文件大?。?/td> | 57K |
| 代理商： | MH88634B |
Advance Information
MH88634B
2-267
18
AGND
Analog Ground.
4-wire ground (AGND). Normally connected to system ground.
19
LRC
Loop Relay Control (Input).
A logic 1 activates the Loop Relay Driver output (LRD).
20
VRLY
Relay Positive Supply Voltage.
Typically +5V. Connects to the relay supply voltage.
21
LRD
Loop Relay Drive (Output).
Connects to the Loop Relay Coil. When LRC is at a logic 1 an
open collector output at LRD sinks current and energizes the relay.
Pin Description (continued)
Functional Description
The MH88634 is a Central Office Interface Circuit
(COIC). It is used to correctly terminate a Central
Office 2-wire telephone line. The device provides a
signalling link and a 2-4 Wire line interface between
the Telephone Line and subscriber equipment. The
subscriber equipment can include Private Branch
Exchanges
(PBXs),
Key
Terminal Equipment, Digital Loop Carriers and
Wireless Local Loops.
Telephone
Systems,
All descriptions assume that the device is connected
as in the application circuit shown in Figure 3.
Isolation Barrier
The MH88634 provides an isolation barrier which is
designed to meet FCC Part 68 (November 1987)
Leakage Current Requirements.
External Protection Circuit
An external Protection Circuit Device assists in
preventing
damage
to
subscriber’s
equipment,
conditions. The type of protection required is
dependant upon the application and regulatorary
standards. Further details should be obtained from
the specific country’s regulatorary body. Typically
you will need lightening protection supplied by
resettable fuses or PTC
TM
and mains crossover
protection via a foldover diode.
the
due
device
to
and
the
over-voltage
Suitable Markets
The MH88634BV-2/BT-2 has fixed 600
line and
network balance impedance for use in North
America and Asia.
The MH88634BV-4 has a fixed 900R impedance and
is also suitable for some applications in North and
South America
Line Termination
When LRC is at a logic 1,
which energizes the Loop Relay (K1), connecting
XLA to XLB and XLC to XLD. This places a line
termination across Tip and Ring. The device can be
considered to be in an off-hook state and DC loop
current will flow. The line termination consists of a
DC resistance and an AC impedance. When LRC is
at a logic 0, the line termination is removed from
across Tip and Ring.
LRD will sink current
An internal Dummy Ringer is permanently connected
across Tip and Ring which is a series AC load of
(17k
+330nF). This represents a mechanical
telephone ringer and allows ringing voltages to be
sensed. This load can be considered negligible
when the line has been terminated.
Depending on the Network Protocol being used the
Line Termination can terminate an incoming call,
seize the line for an outgoing call, or if applied and
disconnected at the correct rate can be used to
generate dial pulse signals.
The DC line termination circuitry provides the line
with an active DC load termination which is
equivalent to a DC resistance of 280
at 20mA
Ringing Equivalent Number
The Ringing Equivalent Number (REN) is application
specific. See the governing regulatory body
specification for details.
Input Impedance
The input impedance (Zin) is the AC impedance that
the MH88634 places across Tip and Ring to
terminate the Telephone line. This is fixed at 600
on the -2 variant and 900R on the -4.
相關PDF資料 |
PDF描述 |
|---|---|
| MH88634CV-K | Central Office Interface Circuit(用于中央辦公電話線的接口電路（在音頻轉(zhuǎn)換設備和用戶線之間提供一個模擬和信號連接）) |
| MH88634K | Central Office Interface Circuit Preliminary Information |
| MH89101 | Passive Line Termination Circuit Advance Information |
| MH89625C | OPS/DID PCM SLIC Preliminary Information |
| MH89726 | MT8972 Loop Extender Circuits Advance Information |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MH88634BT-2 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface Circuit Advance Information |
| MH88634BV-2 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface Circuit Advance Information |
| MH88634BV-4 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface Circuit Advance Information |
| MH88634CV-K | 制造商:ZARLINK 制造商全稱:Zarlink Semiconductor Inc 功能描述:Central Office Interface Circuit |
| MH88634K | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface Circuit Preliminary Information |
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