Harris TSP-21 Telephone Test Set Plus

© Brooke Clarke 2014
Harris TSP-21 Telephone Test Set Plus
Background
Description
    Photos
    Test Set Body
    Test Cord
    Headset
Patents
Related
Links

Background

Got this test set because it allows hands free talking and listening unlike the common buttset (Wiki) which requires either hand holding or craning your neck.
Note that when using a buttset in a crossover box (Wiki) the telephone number of the pairs is not part of the marking.  So you need to use ANAC (Wiki) phone numbers, like 959-1122, 959-1114 or others which tell you which number you are calling from.  This is also very useful when you are wiring a building so that you can connect a given number to a specific telephone set.

Description

Although this test set has a12 button keypad and you can select either pulse or DTMF (Wiki) dialing, it only has last number redial when in pulse mode and when the internal 9V battery is installed (if the test set is disconnected from the line). It also supports Ground Start (Wiki).  There is a 577 Hz test tone generator that also requires the internal battery.  But all the other functions operate without the battery.

Photos

Fig 1 Complete Test Set
Harris TSP-21 Telephone Test Set Plus
 Fig 2 Plantronics StarSet HS0556-1
1188  C
With Switch marked I II III
Harris TSP-21 Telephone Test Set Plus		 Fig 3
Harris TSP-21 Telephone Test Set Plus
Fig 4
Harris TSP-21 Telephone Test Set Plus		 Fig 5
Harris TSP-21 Telephone Test Set Plus		 Fig 6
Harris TSP-21 Telephone Test Set Plus
Fig 7 Test Cord with insulation piercing spike but no bed of nails
471A female connector accepts standard phone tip plugs.
Harris TSP-21 Telephone Test Set Plus


There are three parts to the test set:

Test Set Body

Made utilizing integrated circuits and printed circuit boards.

Test Cord

The 471A dual female connector connects to the test set.  The test set has a couple of phone tip plugs

Headset

Pacific Plantronics Inc. StarSet HS0556-1, 1188  C
Uses two 1/4" phone plugs and is wired with sleeves going to the speaker and tips wired to the mike (BSP 028-351-501 KS 20778) so that it does not matter which way it's plugged in.  There is a switch marked I, II, III, what does it do?  If you have any information on this please let me know.

Note this headset uses ear muff type speakers but the date code 1188 seems to indicate it was made long after the ear supported style was popular, so maybe made to a Bell System specification?

Patents

3168934 Acoustic apparatus, Pacific Plantronics Inc, Feb 9, 1965, 381/338, 181/158 - mike not in front of mouth where it would pickup breath noise, but instead remotely located with noise reduction features.
3184556 Miniature headset-microphone adapted for use with a mask, Pacific Plantronics Inc, May 18, 1965, 379/430 - uses hollow tubes to carry voice to microphone and to carry sound to ear.
3388767 Acoustic noise attenuating apparatus, Pacific Plantronics Inc, Jun 18, 1968, 181/158, 381/338, 381/354, 181/21 - absorbing material at tip of mike boom
3513269 Earform mold for supporting acoustic apparatus on a wearer's ear and method of making the mold, Pacific Plantronics Inc, May 19, 1970,
                381/330, 425/110, 425/182, 264/222, 425/2 -
3524951 Electroacoustic apparatus, Pacific Plantronics Inc, Aug 18, 1970, 379/430 - replaces muff type headphones with in-ear direct porting of sound
3602653 Electroacoustic transducer mount, Pacific Plantronics Inc, Aug 31, 1971, 381/368, 381/375, 381/376 - improved isolation between speaker and mike
3548118 Self-supporting headset, Pacific Plantronics Inc, Dec 15, 1970, 379/430 - support only on ear, no headband, no custom molding to fit ear
3610841 Self-supporting headset, Pacific Plantronics Inc, Oct 5, 1971, 379/430, 381/381, 381/375, 381/330 - support only on ear, no headband
3654404 Headset cradle, Pacific Plantronics Inc, Apr 4, 1972, 379/450 - clips to side of a 500 or 2500 telephone set for storing headset
3604069 Cable strain relief device, Pacific Plantronics Inc, Sep 14, 1971, 24/332, 24/600.6, 24/115.00G - allows easily changing where the clip is along the cable
                Support needed as small force can knock headset off of ear.
3691311 Telephone user set, Pacific Plantronics Inc, Sep 12, 1972, 379/294, 381/107, 379/395 - automatic volume control to suppress noise when no voice

Dracon, Harris Telephone Test, 

Related

Western Electric 202 dial phone
Bell System 302 dial phone
Bell System 500 dial phone
Bell system 2500 Touch Tone phone
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Links

Brooke's: PRC68, Alphanumeric index of web pages, Contact, Products for sale

This page created on 16 Sep 2014