Samsung OFFICESERV 7100 Service Manual page 62

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2.5.7.2 Major Features
The major features of 16SLI2/16MWSLI boards are as follows:
Line Interface
The protection function against the surge from a line, such as Message Waiting Lamp On,
Battery Feeding, Ringing Relay, Hook-Off, etc.
Ring Generator
This receives the square wave input of 20/25 Hz provided from the mother board, creates
the square wave ring signal and supplies the signal to SLT. It supplied a line with the sing
ring signal received from external sine ringer installed separately.
Message Waiting Function
The Message Waiting function periodically turns on the lamp of a MW phone with a MW
lamp when a message remains in the relevant extension line. The MW voltage is shared
with the internal Ringer circuit and the output voltage is more than 100 V. MWSLI requires
the internal ringer circuit to use the MW voltage even if it uses an external ringer.
The period of the MW lamp can be controlled in KMMC #511.
The continuous LED always turns the lamp on. To turn on/off the lamp periodically,
proceed the following procedure:
1) Select [Interrupt LED] and press the [Right] soft button.
2) By using the [Right] soft button, move to the time period.
3) Enter the ring period data in the sequence of On Time and Off Time.
Le79555-2QC
The Le79555 is Subscriber Line Interface Circuit IC manufactured by Legerity Inc.
Its package tpe is 3-Pin QFN and includes the polarity reverse function.
Interworking with Le58QL021 QSLAC I.C, it performs the main functions of the subscriber
interface.
Le58QL021
The Le58QL021 is Quad Low Voltage Subscriber Line Audio Processing Circuit I.C
manufactured by Legerity Inc. A single I.C has 4-Codec and filter and is connected to 4-
SLIC via the SPI bus. With the internal filter, it can be programmed the following items by
using the software:
SLIC device input impedance
Transhybrid balance
Transmit and receive gain
Equalization(frequency response)
Digital I/O pins
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