Telephone Lab
Additional Information
Notes:
- Obtaining equipment. The project requires a large number of telephones that are identical. At Hope College, these telephones were obtained during the upgrading of dormitory telephones. Approximately 200 identical working telephones which had been removed from dormitory rooms were obtained. For a group of 25 people to carry out the a minimum number telephones which would be necessary is approximately 75.
- Testing working telephones. The basic talking and listening function of the telephone can be tested using a test phone and a known working telephone. The telephones can be connected together and powered by a 9 V battery. Note: this will not activate the dialing and ringing function.
- Equipment needed. For each group of 4 people the following additional equipment is needed:
- 1 Known working telephone (which is never dismantled).
- 1 A working telephone with the cover removed for reference use.
- 1 A means of connecting two phones together powered by a 9 V battery.
- Introduction of known problems. For the section of the project involving troubleshooting, a known problem (or problems) are introduced into the telephones. The problem must be detected and repaired. It is recommended that a variety of problems be used and randomly distributed throughout the group. The following are some simple problems which can provide a reasonable troubleshooting experience for the novice. For an additional challenge, more than one problem can be included.
- Handset speaker connection broken
- Handset microphone connection broken
- Ringing mechanism disconnected.
- Connections broken at main circuit board.
- Latch switch disconnected.
- Making a primitive telephone. It is possible to communicate back and forth using the speakers removed from a telephone handset. The speakers can be connected via a two-conductor cable. Individuals can talk back and forth using this type of primitive telephone. This has been found to be effective over a distance of up to 50 m (150 ft).
© 2001 John J. Krupczak, Jr.
All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of the author is prohibited.
Last updated January 10, 2001.