TC-1 (SERVICE TEST MODEL) CLASS "A" EVALUATION

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03330A003300030001-7
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 23
• Document Creation Date: December 27, 2016
• Document Release Date: April 29, 2014
• Sequence Number: 1
• Publication Date: February 17, 1964
• Content Type: REPORT

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A&A Report No. 477
TC-1
(Service Test Model)
CLASS "g EVALUATION
Project No. 2658
SECRET
Date: 17 Feb. 1964
GROUP 1
Excluded from automatic
downgrading and
declassification
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TABLE OF CONTENTS
ABSTRACT
1. INTRODUCTION
2. SUMMARY OF TEST DATA AND COMPARISON WITH THE
ENGINEERING MODEL AND MANUFACTURER'S DATA
3. DETAILS OF TEST DATA
3.1. Mechanical Section
3.1.1. Mechanical Inspection
3.1.2. Size and Weight
Page
1
2
3
3
3
3.2. Test Section 4
? 3.2.1. TC-1 Record, Playback and
Erase Characteristics
3.2.2. Operational Test
(Message Transmission Over Phone Lines)
3.2.3. Pperational Test - Encoding 7
3.2.4. Battery Current Drain 9
3.2.5. Temperature Tests 10
3.2.6. Vibration Test 11
4. CONCLUSIONS 13
5. RECOMMENDATIONS 14
LIST OF FIGURES
Figure 1
Figure 2A
Figure 2B
Figure
3
Figure
4
Figure
5
- Sanborn Recording - TC-1 Signal After
Transmission
- Correct Encoding
6
8
Errors Generated During Encoding By
Allowing Cap To Spring Back Unchecked 8
Photograph - TC-1 15
Photograph - TC-1 in Record Position 16
Photograph - TC-1 With Carrying Case
and Accessories 17
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ABSTRACT
A Class A evaluation was performed on the
(service test model) by the R&D Laboratory.
The TC-1 performed satisfactorily at room temperature. During temperature
extremes the communicator failed to meet manufacturer's WPM, specifications.
It ran about 70 WPM slow.
There were no encoding Or transmission errors at any temperature,.
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1. INTRODUCTION
The TC-1
is a completely transistorized, miniature
50X1
tape recorder
designed to manually
record a precoded message and play-
back the message at a rapid rate
50X1
The communicator produces a teletypewriter
five level, eight unit
inverted Baudot code. The coder
is arranged so that when the message is
played back the letters can be read
50X1
but the message will be backwards.
11
The TC-1 cummunir s ar ator i mannfured
by the
50)(1
1-
50X1
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2. SUMMARY OF TEST DATA AND COMPARISON WITH THE
ENGINEERING MODEL AND MANUFACTURER'S VDATA
ITEM
TEST DATA
TC-1 ENGINEERING MODEL
MANUFACTURER'S DATA
Seven volt battery
current drain
Record - 2.3 ma
Playback - 3.4 ma
Erase - 4.1 ma
Record - 1 ma
Playback - 3 ma
Erase - 4 ma
None
Message error rate
0.07
2.57
2.07
Code
Eight element
inverted Baudot
Eight element
inverted Baudot
Eight element
inverted Baudot
Word capacity
115 words of
6 characters
100 words
, 100 words
Transmission speed
1071 - 1182 WPM
1192 - 1218 WPM
1140- 1260 WPM
Transmission on
air time
6.0 - 6.5 seconds
4.93 - 4.94 seconds
Erase
characteristics
22 - 47 db
reduction of signal
after erasure
depending on
temperature
19 db
Operation at
temperature
extremes
70 WPM slow
Operation after
vibration
Satisfactory
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3. DETAILS OF TEST DATA
3.1. Mechanical Section
3.1.1. Mechanical Inspection
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The TC-1 appears to be well constructed and mechanically sound. It has
several minor faults which should be corrected.
In the record position the cap indexes sloppily. Although the wrong'
character cannot be selected there is a large amount of play in the cap ,
on either side of the correct character.
During the 110?F, 907,. humidity test the paint on the unit began to peel.
During the same test the windup key rusted badly.
The red marks signaling the end of tape are difficult to see.
The on-off switch is spring loaded and can slip out of the operator's
fingers to the off position. If the TC-1 is operated with the remote
transducer, the on-off switch is difficult to locate by touch while the
unit is in an operator's pocket.
When the transducer is inserted into the TC-1 it sometimes makes a poor
contact. The communicator should be tried out immediately after the
transducer is inserted to make sure the transducer is working properly.
3.1.2. Size and Weight
TC-1
Size : 4 1/4 L x 1 3/4 D
Weight : 14 ounces
Remote Unit
Weight : 3 ounces
Carrying case with keys and batteries
Size : 6 3/4 L x 6 5/8 W x 2 5/8 D
Weight : 13 ounces
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3.2. Test Section
3.2.1. TC-1 Record, Playback and Erase Characteristics
Test Setup:
TC-1
Remote
Transducer
Sanborn
Model 650
Recorder
Test Procedure:
(a) A message was recorded on the entire length of the tape.
(b) The tape was played back and the output recorded on photographic
paper by means of the Sanborn recorder.
(c) The Words Per Minute were calculated at the beginning, middle, and
end of the tape by measuring the time of transmission for two words
(12 characters).
? (d) The overall speed was calculated by measuring the playback time of
the complete reel of tape and counting the total number of characters
transmitted.
(e) The element, character, and stop-space times were recorded.
(0 The amplitude variation of the pulses was noted.
(g) The tape was started in the middle of a message and the time required
before reception of characters was noted.
(h) The tape was erased and the erase characteristics were noted.
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3.2.1. TC-1 Record, Playback and Erase Characteristics (Continued)
Test Results:
Words Per 'Minute
Beginning of tape 1182
Middle of tape 1173
End of tape 1158
Overall
1170
Word capacity
115 words
Character length
8.2 - 9.1 ms
Element length
1.05 - 1.18 ms
Stop-Space length
1.96 - 2.45 ms
Amplitude variation
3.6 db
' DB reduction of signal after erasure
32.6
After restarting the tape in the middle of a message approximately
0.15 second was required before the characters appeared (the amplifier
was evidently off) and 0.213 - 0.232 second total time was required
before the characters were received undistorted.
3.2.2. Operational Test (Message Transmission Over Phone Lines)
Test Procedure:
(b) The message was sent twice (TEST 1 and TEST 2) and recorded on
photographic paper by means of the Sanborn recorder.
Test Results:
See Figure 1
The recorder gain controls were unchanged between TEST 1 and TEST 2.
Timing lines are 10 ms apart.
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3.2.3. Operational Test - Encoding
Test Procedure:
An attempt was made to generate encoding errors with the TC-1.
Test Results:
With a little care a message can be encoded with no.errors. However,
if the cap is allowed to spring back up unchecked while encoding, errors
can be generated. See Figure 2B.
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TIMING LINES-0.01 SEG., APART
FIGURE 2A
CORRECT ENCODING
TIMING LINES-0.01 SEC. APART
FIGURE 2B ERRORS GENERATED DURING ENCODING BY
ALLOWING CAP TO SPRING BACK UNCHECKED
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3.2.4. Battery Current Drain
Test Setup:
TC-1
Weston Model 931
DC Milliammeter
Mallory #303383
Mercury Battery
7.0 volts
Test Conditions:
A fresh battery with open circuit voltage of 7.2 volts was used.
Test Procedure:
A DC milliammeter was connected in series with the TC-1 battery and the
current drain was measured with the TC-1 operating in the record, play-
back and erase positions.
Test Results:
Record 2.3 ma
Playback 3.4 ma
Erase 4.1 ma
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3.2.5. Temperature Tests
Test Setup:
1
TC-1
Remote .
Transducer
TEMPERATURE CHAMBER
Sanborn
Model 650
Recorder
Test Procedure:
(a) The TC-1 remained at the specified temperature for one hour before
measurements were conducted.
(b) Tests were conducted at 110 F with 90% humidity and at 0 F.
(c) Each character was recorded three times.
(d) All data was obtained on photographic paper by means of the Sanborn
recorder.
(e) The tape was played back and the following was noted:
(1) Any recording or transmission errors
(2) Words Per Minute (measured by the transmission time for
12 characters)
(3) Playback time for a complete reel of tape from red section
of tape to end)
(f) The tape was erased once and played back to note the erase
characteristics.
(g)
After the temperature tests the words per minute and playback time
at room temperature for a complete reel of tape (from red section
of tape to end) was noted.
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3.2.5. Temperature Tests (Continued)
Test Results:
ITEM
0 oF
110oF
Room Temperature
Encoding or
playback errors
,None
None
None .
Words Per Minute
1106 - 1112
1071 - 1074
1158 - 1182
Playback time for
a complete reel
of tape
6.203 seconds
6.464 seconds
6.00 seconds'
DB reduction of
signal after erasure
47.2
22.8*
32.6
*Not a complete erasure of all characters. Although the signal was
'considerably reduced in amplitude a few of the characters could be
picked out of the background noise on the Sanborn recording.
3.2.6. Vibration Test
Test Procedure:
(a) The fixture without the TC-1 was vibrated to check for resonances,
then the TC-1 was vibrated in two mutually perpendicular planes
(flat and standing up) at a constant displacement of 0.4 inch
double amplitude from 5 to 10 cps, and at a constant acceleration
of 2 G's from 10 to 500 cps.
(b) The sweep rate was set to 15 minutes from minimum to maximum and
back to minimum.
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3.2.6. Vibration Test (Continued)
(c) Three complete cycles were run for a total of 45 minutes of
vibration testing in each plane.
(d) The TC-1 record, playback, and erase functions were checked after
the test and the playback time for a complete reel of tape was
noted.
Test Results
No resonant points were observed. The TC-1 encoded and transmitted all
characters correctly. The tape speed and erase characteristics were
satisfactory.
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4. CONCLUSIONS
The TC-1 performed satisfactorily except that it failed to meet the
manufacturer's specifications for words per minute at both temperature
extremes.
There were no encoding or transmission errors.
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5. RECOMMENDATIONS
The TC-1 cap should be arranged so that it indexes sharply.
The communicator speed should be brought up to specifications at the
temperature extremes.
The communicator should employ a more weather resistant paint.
The windup key should be made of a non-ferrous material.
The on-off switch should have an external button attached to make it
easier to grasp.
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Accessories
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ADDENDUM
In testing the DR-8, tests were run on TC.1 serial No. 138 to
determine whether it was operating properly,
The speed of the TC-1 varied from 1127 to 1176 wpm. This is not
within specifications.
The numbers 3 and 6 do not appear on the recording head.
When the TC-1 is placed on
switch must be pressed away
hold the TC-1 next
, the ON-OFF
while trying to
This is difficult to do.
Operation would be simplified if the swirtch moved in the opposite
direction (down toward the telephone for ON, up for OFF).
While transmitting with the TC-1, it is possible to move the RECORD-
SHIFT button. This will lock the TC-1 and the button will have to
be placed in the PLAYBACK position before transmission is possible.
The TC-1 must be brought up to specifications in PLAYBACK speed.
Neither the previous model tested nor the present model of the TC-1
did 1200 wpm. In both models the top speed was less than 1200 wpm,
This makes it easy for the TC-1 to slip out of tolerance on the
low end.
Tho numbers 3 and 6 should be added to the record head.
Operation of the ON-OFF switch should be reversed.
There should be a positive loci on the RECORD-SHIFT button locking
it it the PLAYBACK position.
GROUP I
Excluded from automatic
downgrading and
declascIficatIon
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50X1
50X1
50X1
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SECRET
SECRET
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