IBM ThinkPad 755CX Manual page 281

Installation and Operating Instructions Addendum for United
Kingdom Users
Users of the IBM ThinkPad 755CX modem function in the United Kingdom (U.K.) must
pay close attention to the statements contained in this Addendum.
Modem Connection
1. The modem is suitable for connection to the public switched telephone network
(PSTN) provided by British Telecommunications plc or Hull City Telephone
Department. (Direct exchange lines only, not shared service or 1-1 carrier
systems.)
2. It is suitable for use only on telephone lines provided with Loop-Disconnect or
Multi-Frequency Dialling facilities.
3. These modems are only approved for compatible PBX's. IBM should be
consulted for an up-to-date list of PBX's with which the modem is compatible.
4. They are suitable for connection to PBX's which return secondary proceed
indication.
5. If a modem is to be used with a PBX which returns secondary proceed indication,
no more than 2 pauses of four seconds duration each should be inserted
between the initial PSTN access digit and the number to be dialled. This is to
avoid interference to the BT network.
6. If a modem is to be used with a PBX which has extension wiring owned by BT,
connection of the modem to the PBX can only be carried out by BT; or, by the
authorized maintainer of the PBX unless the authorized maintainer has been
given 14 days written notice that the connection is to be made by another
person, and that period of notice has expired.
7. There is no guarantee of correct working in all circumstances. Any difficulties
should be referred to IBM.
8. Some network operators require that intended users of their network request
permission to connect and for the installation of an appropriate socket.
Ringer Equivalence Number
The ringer equivalence number (REN) of this modem is 1.
REN is a guide to the maximum number of apparatus that can be simultaneously
connected to one telephone line. The REN value of each apparatus is added
together, and should not exceed 4.
Warranties and Notices
Appendix E. Product Warranties and Notices
265