3Com ISDN Modem User Manual page 145

TollMizer
Allows you to place a data call over a voice channel, saving
the extra cost of the data channel. Your telephone company,
ISP, and the device into which you are calling must all
support this feature.
V.120
A rate adaption scheme that converts transmission rates from
a range of 300 bps to 115.2 Kbps to the B channel
56 Kbps or 64 Kbps rate. V.120 is used for communication
between two computers.
G 5
LOSSARY