Transmitter Theory Of Operation - Typical Transmission - OKIDATA OF1000 Service Manual

2.2 TRANSMITTER THEORY OF OPERATION
2.2.01 Typical Transmission
When a telephone number is dialed through the Okifax 1000 (either manually or through auto-dial), a
connection will be established with the receiving station through the Public Switched Telephone Network
(PSTN). When the call is answered, the operator will hear the Called Equipment Device (CED) tone from
the receiving station. With CED received, the transmit machine acknowledges that the connection is
established and proceeds to the CCITT T.30 300 bps handshake procedure.
NOTE:
Refer to the Receive
overviews of 300 bps handshaking.
Refer to the Transmit Block Diagram for an overview of G3 Transmit Operations.
When the DIS (Digital Identification Signal) is received, G3 mode transmission is possible and the Okifax
1000 starts scanning the document, page by page. The image data is temporarily stored in FIFO (First In
First Out) memory until it becomes valid for transmission. In about 3 seconds, the machine will receive
CSI (Called Subscriber Identification) from the distant station. After reading the document pages and
storing the image data in memory, the machine begins the handshake with the distant station. If the 9600
bps training is successfully completed, the machine will start transmitting the image data in digital, coded
form. Training is a high speed data pattern transmitted to the receive modem. This training data pattern
causes the receive modem to synchronize with the transmit modem. If the training fails due to the line
condition, an automatic fallback to a lower rate will occur. The result will be indicated on the LCD display.
As the machine transmits each page of image data, the page count on the LCD display will increment.
Training is used :
· To test the line condition for valid transmissions at a particular data rate.
The TCF consists of 100 binary 0s transmitted in a burst. At least 98% accuracy
must be achieved before transmission can take place at that data rate.
· By the receiving station in setting preliminary equalization for the current line conditions.
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)
and Transmit Handshake Procedure Block Diagrams for functional
Service Guide OF1000
Chapter 2 Principles of Operation
Page: 24