IBM ThinkPad X20 Supplementary Manual page 81

Not all phones connected to the phone port will respond to incoming ringing.
Do not report this as a fault unless the same phone will not respond to
ringing when connected to a standard phone socket.
This equipment shall not be set up to make automatic calls to the Telecom 111
Emergency Services.
The grant of a Telepermit for a device in no way indicates Telecom acceptance
of responsibility for the correct operation of that device under all operating
conditions. In particular, higher speeds at which this modem is capable of
operating depend on a specific network implementation which is only one of
many ways of delivering high quality voice telephony to customers. Failure to
operate should not be reported as a fault to Telecom.
In addition to satisfactory line conditions a modem can only work properly if:
it is compatible with the modem at the other end of the call and,
the application using the modem is compatible with the application at the
other end of the call - e.g. accessing the Internet requires suitable software
in addition to a modem.
This equipment should not be used in a manner which could constitute a
nuisance to other Telecom customers.
Some parameters required for compliance with Telecom's PTC Specifications
are dependent on the equipment (PC) associated with this modem. The
associated equipment shall be set up to operate within the following limits for
compliance with Telecom specifications:
There shall be no more than 10 call attempts to the same number within
any 30 minute period for a single manual call initiation
The equipment shall go back on-hook for a period of not less than 30
seconds between the end of one call attempt and the beginning of the next.
Automatic calls to different numbers shall be not less than 5 seconds apart.
When used in the Auto-Answer mode, the S0 register must be set with a
value between 2 and 5. This ensures:
A person calling your modem will hear a short burst of ringing before the
modem answers. This confirms that the call has been successfully switched
through the network.
Caller identification information (which occurs between the first and
second ring cadence) is not destroyed.
71
Appendix C. Notices