In the U.s., a support agreement is available for repair and service.
Refer to the form that was wrapped with the manual. For additional
information, contact the Calculator Service Center (see the inside of
the back cover).
Radio Frequency Interference
The HP-28S generates and uses radio frequency energy and
may interfere with radio and television reception. The calculator com-
plies with the limits for a Class B computing device as specified in
of Part 15 of FCC Rules, which provide reasonable protec-
tion against such interference in a residential installation. In the
unlikely event that there is interference to radio or television reception
(which can be determined by turning the HP-28S off and on or by
removing the batteries), try:
• Reorienting the receiving antenna.
• Relocating the calculator with respect to the receiver.
For more information, consult your dealer, an experienced
radio/television technician, or the following booklet, prepared by the
Federal Communications Commission: How to Identify and Resolve Ra-
dio-TV Interference Problems. This booklet is available from the U.s.
Government Printing Office, Washington, D.C. 20402, Stock Number
004-000-00345-4. At the first printing of this manual, the telephone
number was (202) 783-3238.
West Germany. The HP-28S and the HP 82240A printer comply
with VFG 1046/84, VDE
and similar non-interference
If you use equipment that is not authorized by Hewlett-Packard, that
system configuration has to comply with the requirements of Para-
graph 2 of the German Federal Gazette, Order (VFG) 1046/84, dated
December 14, 1984.
A: Assistance, Batteries, and Service