Lenovo ThinkPad T420 User Manual page 68

You can use the modem only on a public-switched telephone network (PSTN). You cannot use a private
branch exchange (PBX) or some other type of digital telephone extension line. If you connect the modem to
a line other than PSTN, an error message appears, preventing you from using the line. If you are not sure
which kind of phone line you are using, contact your telephone company.
DANGER
To avoid shock hazard, do not connect the cable to or disconnect the cable from the telephone
outlet on the wall during electrical storms.
Note: Your computer might have both the modem connector and the Ethernet connector. Be sure to
connect your cable to the correct one.
Telephony features
The built-in modem has the following telephony features:
Industry standard modem support up to 56 Kbps:
Data protocols
• Bell 103 (300 bps)
• Bell 212A (1200 bps)
• V.21 (300 bps)
• V.22bis (2400 bps)
• V.34bis (33600, 31200 bps)
• V.34 (28800, 26400,24000,21600,19200,16800,14400,12000,9600,7200,4800 bps)
• V.90 (56000 bps downstream only)
Error correction/Data compression protocols
• MNP2-4 (Microcom error correction)
• V.42 (error-correcting procedures for DCEs using asynchronous automatic dialing and control)
Data compression protocols
• V.42bis (DCE data compression)
• V.44
• MNP5 (Microcom data compression)
Miscellaneous protocols
• V.8 (startup sequence)
• V.80 (video phone)
• Fast Connect
Note: This function can work only if the phone line and server equipment at your ISP (Internet Service
Provider) access point are compatible with it. Check with your telephone company and ISP.
• Modem on Hold
Note: This function can be used only in certain countries or regions, because it relies on the specifications
of the Call Waiting function and Caller ID function, which each country or region sets independently. It has
been tested and shown to work in the United States and Canada. In addition, the function can work only if
it is compatible with the server equipment at your ISP.
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User Guide