Ricoh A250 Service Manual page 438

2.4.3 V.8/V.34 PROTOCOL
NOTE: 1) Refer to "V.8/V.34 Training Manual" for overall information about
V.8/V.34 protocol.
2) This section explains machine specific functions only.
V.8 in Manual Reception
This machine starts the V.8 procedure in order to allow V.34 communication in
manual reception, though some other fax machines do not.
Refer to "V.8/V.34 Training Manual – section 3.1" for detailed procedures.
Shift-down Conditions
One-step Shift-Down from the Receiving Terminal
33.6kbps
1st block
33.6kbps
33.6kbps
31.2kbps
2nd block
31.2kbps
2nd page
The diagram shows the protocol used by this model acting as the receiving
terminal.
If the machine has sent two PPRs for one ECM block, it will request the sending
terminal to make a one-step shift-down in the next control channel.
N eor : Number of frame re-transmissions remaining until the Tx terminal sends
DCN to terminate the communication. This is fixed at "9", and is not adjustable.
SM
FAX COMMUNICATION FEATURES
TX RX
Fax data
P P S - N U L L
P P R
Fax data
P P S - N U L L
P P R
Fax data
Shift-down
request
P P S - N U L L
M P h
M P h
M C F
Fax data
P P S - M P S
M C F
Fax data
P P S - E O P
M C F
D C N
2-17
N
eor
9 (default)
8
7
9
9
9
A891D532.WMF
A250