Samsung OFFICESERV 7100, Service Manual

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OfficeServ 7100 Service Manual
© SAMSUNG Electronics Co., Ltd.
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2.5.11 16DLI/16DLI2 Board
The 16DLI board provides the interface circuit of 16 ports digital phones or DPIMs, which
are the terminals for the OfficeServ 7100 system. QDASL that enables interfacing of four
2B+1D(two voice channels of 64 kbps and one signal channel of 16 kbps) is used for each
port of the board.
A full-duplex AMI coding method is used for signal forwarding. End-to-end communications
support two voice channels of B1 and B2 so that two stations can be connected with one
port.
Transmission between the 16DLI board and digital phone is made at 192 kbps. 16 kbps
from 48 kbps where 144 kbps of 2B+1D is excluded is used for synchronization and
remaining 32 kbps is used for transferring null data. Lines of AWG 26 thick are used as
transmittance lines between the 16DLI board and digital phone and maximum transmittance
distance is 400 m.
The DLI board supplies the power of –48 V to the phone and is configured with the poly
switch that disconnects over-current and circuits for digital interfaces. This board controls
-48 V of power on or off through the FET inside of the 8DLI board.
The UART inside of QDMC has three Rx and Tx buffers of 1 byte. If more than two
buffers are used, data will have problems. Therefore, check the status of the buffers before
transferring the data. Once the QDMC converts parallel data to serial data and transfers the
converted data to QDASL, the QDASL converts the data into the AMI code and transfers
the data to the digital phone. The signaling data created from the digital phone convert
serial data to parallel data in the UART Rx buffer of the QDMC through the QDASL and
transfer the converted data to the CPU.
-48 V of power on/off is controlled through the FET in the 16DLI board.