ZM-4 Bridge

Brooke Clarke, N6GCE  2003

ZM4 Bridge Front Panel . ZM4
          Bridge Lid w/ Instructions

Background

Telephone, and other wire, lines go bad and need to be repaired.  In order to locate shorts and opens an impedance bridge can be used.  The ZM-4 was designed for this purpose.
This may be the same as the Leeds & Northrup 5430-AM-1 Test Set.
This may be the same as the Beckman Long Line Telephone Test Set KS-14959 (See BSP 100-815-101).
This is very similar to the Shallcross Wheatstone Bridge 6101.

Documents

       The manuals on the CD-ROM have Adobe Acrobat bookmarks, but no other manual enhancements.
A CD-ROM with the following documents is available for $15.00 ($17.00 for international mailing):
MIL-B-3667B, 3067BN1, 3067INA, 3067CAN - Mil specs for the production of the ZM-4
TM 11-2019 Manual covering the ZM-4A/U and ZM-4B/U also the I-49() Resistance Bridges 70 pages.
This is a comprehensive manual including a number of practical example cases.  Includes the case where a telephone system has not just a simple home run pair, but a more realistic situation where there are bridges where the branches and main line use different gauges of wire.

Also has a theory section describing the different types of bridges.
TM 11-6625-249-12P Repair Parts  14 pages
TM 11-6625-249-34P Repair parts & Tools  23 pages

ZM-4 Manuals to U.S. mailing address $ 15.00

ZM-4 Manuals to international  mailing address $ 20.00

  or using USPS send payment to:

Brooke Clarke
3425 Deerwood Dr.
Ukiah, CA 95482-7541

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Page created 27 Sep 2003.