Automatic Fall-Back Mode - OKIDATA OF2600 Service Manual

Page: 7
Service Guide OF2200/2400/2600
Chapter 1 Principles of Operation

1.1.04 Automatic Fall-back Mode

The unit will change the message transmitting speed according to the following fall-back plan. The first
page of the message is transmitted at 14.4 kbps (Okifax 2200 communicates at 9600 bps maximum). The
receiving station will continuously monitor the received data. If the receiving station detects six or more
consecutive error lines during reception of a single page, or if the total number of errors detected during
the reception of a single page exceeds 10% of the data on the transmitted page, it will return a Retrain
Negative (RTN) signal to the transmitting station upon termination of the page reception. With an RTN
signal received, the transmitting station will downgrade its speed by one level (to 12 kbps in this case) and
continue transmission of the next page. Similarly, should the transmitting station again receive an RTN
signal from the receiving station, it will downgrade the speed another level.
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