Toshiba DP120F Service Manual page 581

b-2) Probing/Ranging (Phase 2)
Line characteristics are measured, then the parameter setting for modulation such
as the modulating speed, is made.
• Transmitter
Signal name
INFO sequence
Tone B
Tone B
Line probing signal
L1
Line probing signal
L2
• Receiver
Signal name
INFO sequence
Tone A
Tone A
INFO sequence
March 2000 © TOSHIBA TEC
Abbreviation
INFO0c It indicates modem capability such
as modulating speed and frequency
transmission capability (two fre-
quency bands - high and low - used
for measuring the line characteris-
tics), and requests for adjusting.
B Synchronization between modems
B by 1200-Hz tone
L1 Tone for analyzing the line charac-
teristics by probing
L2
Abbreviation
INFO0a It indicates the modem capability
such as the modulating speed and
frequency transmission capability.
A Synchronization between modems
A by 2400-Hz tone
INFO0h Based on the analysis of the line
probing signal sent from the trans-
mitter, it indicates the pre-empha-
sis filter and modulating speed to
be used for the data transmission.
Meaning
Meaning
9-17 DP120F/DP125F Dialing and Communication Procedure
Remark
Transmission rate: 600 bps
B is a signal that shifts phase
B 180°.
Probing is to measure the line
characteristics.
Tone between 150 Hz and
3750 Hz in units of 150 Hz
Remark
Transmission rate: 600 bps
A is a signal that shifts phase
A 180°.
Transmission rate: 600 bps