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G3 FACSIMILE COMMUNICATIONS
• RNR and RR
On receivers whose printing speed is slower than the data receive speed,
the receive buffer sometimes becomes full or busy. In this case, reception
of the next block is not possible until new free memory appears after print-
ing of already received blocks has ended. If this happens, the receiver out-
puts RNR to communicate to the transmitter that the next blocks cannot be
received temporarily (receiver is busy).
When the transmitter receives RNR, RR is repeatedly output to inquire as
to the state of the receiver. When the receiver receives RR, RNR is
returned for the period that the receiver is busy. When the receiver no
longer is busy due to end of printing, for example, MCF is output to com-
municate that the next block can be received. The transmission times of
RNR and RR are determined by timer T5. On facsimiles having a small
page buffer, instances where ##753, ##758 and ##783 errors frequently
occur can be remedied by lengthening the timer T5 setting.
5–130
Calling Side (transmitter)
Transmission of
1st page
"Are you ready?"
"Are you ready?"
"Are you ready?"
Transmission
of 2nd page
Line disconnected
Frame 0
Frame 1
2400bps
Frame 255
PPS-MPS
PPR
Frame
Frame
PPS-MPS
RNR
RR
RNR
RR
RNR
RR
MCF
Frame 0
Frame 1
Frame
Fig. 5-89 RNR and RR
Called Side (receiver)
"Not ready to
receive"
"Not ready to
receive"
"Not ready to
receive"
"Received
the page."
Line disconnected
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