Receiver Theory Of Operation - OKIDATA OF1000 Service Manual

Page: 35
Service Guide OF1000
Chapter 2 Principles of Operation

2.3 RECEIVER THEORY OF OPERATION

NOTE:
Refer to the G3 Receive Operation Block Diagram .
2.3.01 Operator Panel
Through the operator panel, the user initiates manual receive operations and sets auto-answer
options.
2.3.02 Line Board
The line board provides the RJ-11 connection used to receive data from the PSTN or PBX.
2.3.03 Network Control Board (NCU)
The NCU receives the modulated data from the line board and sends it to the modem (located on
the MCNT board). The operation of the NCU in the receive mode is very similar to the transmit
mode. However, during receive operations, the NCU also functions as an amplifier for the
received signal.
2.3.04 Modem
The modem demodulates the data from the G3 (9.6, 7.2, 4.8, or 2.4K bps) scheme that was
determined during handshaking. The data is then sent to the read-only memory for temporary
storage. The storage time is dependent on whether the machine is printing real-time or from
memory.
2.3.05 Decoder
The decoder decodes the MH, MR, or MMR data from the RAM into lines of picture data that are
1,728 bits in length. After the data has been received, demodulated, and decoded, it is transferred
to the PCNT board.
2.3.06 Document Size
Since the available printing area of the printer is smaller than the paper size, document contents
may be missed on both sides of the paper, or a document image having the same length as the
printing paper may be split into separate pages during printing. To prevent this, the Okifax 1000
automatically sets the proper reduction ratio within the range of 90 to 100% if the RX
REDUCTION function has been set ON. If a received document image is longer than the available
printing length, the excess part of the image is eliminated. If the SPLIT PRINT function has been
set ON, the excess image will be printed on the next page.
Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business
Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)