Samsung OFFICESERV 7100 Service Manual page 59

The highway channel in the 4SLM board is determined by the SPI command in software
and reads/writes only the channel information required for the system highway through
74LCX125 by using the TSAC signal provided from Le88241.
SPI: The 4SLM board is controlled via the SPI interface provided by the UNI board.
SPI_DIO/SPI_SCK/SPI_CS are provided by the UNI board and DIN/DOUT pins are
hardwired in Le88241 to make the same signal path for Data In/Out.
All controls for the 4SLM board are performed through the register setting and the
information reading of Le88241.
Dual ABS Part
The 4SLM board performs the SLT interface function by using Le88241, which is 2-Channel
Auto Battery Switching(ABS) one-chip solution chip by Legerity Inc. The Le88241
provides the 2-port SLT interface and embeds the Sine wave ringing generation circuit so
the separate ring generation circuit is not required. Up to three boards can be mounted on
the UNI board. The board is controlled by the MP10/11 board bia the UNI boards by using
the SPI bus. The most operations and functions of the 4SLM board are determined by
Le88241.
The major features of Le88241 as follows:
Sine Wave Ringing Generation
DC Feeding
Loop supervision detection
2/4-wire balance
Transmit/receive gain control
A-law/u-law selection
The Le88241 consists of the following blocks:
Digital Interface Block
This is the interface block with the microprocessor. The L288241 provides GCI mode
or PCM/MPI and the 4LSM board uses PCM/MPI Mode, i.e. Voice PCM and Data MPI
separated. In Digital Interface, the PCM/MPI Mode is selected by applying '1' to the
CS-PG pin or a clock to DCLK. A mode is selected by supplying DCLK in the 4SLM
board. The MPI Interface uses the SPI bus. DU/DD, i.e. Data in/out, are separated in
the Le88241, but the two pins are connected in the outside of the chip in term of
hardware and is used as the DIO pin.
PCM Interface Block
DRA, DXA, CLK and FS pins are in charge of the PCM interface and channels are
selected by using the SPI command. When the required channel is accessed, the
Le88241 creates the time slot control signal. In addition, the 4SLM board allows the
corresponding channel to access to the system highway by controlling the signal by
using 3-state buffer.
© SAMSUNG Electronics Co., Ltd.
OfficeServ 7100 Service Manual
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