Plantronics T20 - Manual (Page 6)

FCC Requirements—Part 68
This equipment complies with Part 68 of the FCC Rules. The FCC Part 68 Label is
located on the bottom of the enclosure. This label contains the FCC Registration
Number and Ringer Equivalence Number (REN) for this equipment. If requested, this
information must be provided to your telephone company.
The REN is useful to determine the quantity of devices you may connect to your
telephone line and still have all of those devices ring when your telephone number is
called. In most, but not all areas, the sum of the RENs of all devices connected to
one line should not exceed five (5.0). To be certain of the number of devices you
may connect to your line, as determined by the REN, you should contact your local
telephone company to determine the maximum REN for your calling area.
Connection to the telephone network should be made by using standard modular
telephone jacks, type RJ11. The plug and/or jacks used must comply with FCC Part
68 rules. If this telephone equipment causes harm to the telephone network, the
telephone company will notify you in advance that temporary discontinuance of
service may be required. But if advance notice isn't practical, the telephone
company will notify the customer as soon as possible. Also, you will be advised of
your right to file a complaint with the FCC if you believe it is necessary.