MH88628 查看數據表（PDF） - Mitel Networks

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产品描述 (功能)

生产厂家

MH88628

Central Office SLIC

Mitel Networks 

MH88628

Preliminary Information

Longitudinal Balance

Ring Trip Detection

The longitudinal balance specifies the degree of

common mode rejection in the 2 to 4 wire direction.

Precision laser trimming of internal resistors in the

hybrid ensures good overall longitudinal balance.

The interface circuitry can operate in the presence of

induced longitudinal currents of up to 40mA at 60Hz.

The interface permits detection of an Off-Hook

condition during the ringing. If the subscriber set

goes Off-Hook when the ringing signal has been

applied, the DC loop current flow will be detected

within approx. 100msecs and the SHK output will go

low. The ring relay is automatically disabled by the

internal hardware.

Off-Hook and Dial Pulse Detection

Control Decode

The SHK pin goes low when the DC-loop current

exceeds a specified level. The threshold level is

internally set by the bias voltage of the switch-hook

detect circuitry. Dial pulse can be detected by

monitoring the interruption rate at the SHK pin.

These dial pulses would be debounced by the

system’s software.

The different modes of operation are selected by

decoding the SEL1 and SEL2 inputs (see Table 5).

DTMF

The DTMF tones are transmitted and received at the

4-wire port.

Z

10kΩ

MH88628

Z

-

TX 25

+

GTX1 28

RTX

GTX0 27

10kΩ

Z

Transmit Gain:

(Tip-Ring to Tx)

AV= -20log [ 0.5 + 5kΩ ]

RTX

RTX =

5kΩ

10(-AV/20)-0.5

Example

RTX=38kΩ; AV= +4dBV

2-206

-

+ 10kΩ

RX 26

GRX1 30

RRX

GRX0 29

10kΩ

Receive Gain:

(RX to Tip-Ring)

AV= -20log [ 0.5 + 5kΩ ]

RRX

RRX =

5kΩ

10 (-AV/20) -0.5

Example:

RRX=4.6kΩ; AV= -4dBV

Figure 3 - Gain Programming with External Components

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