NEC TTS 26B User manual

l NSTRUCTION MANUAL
FOR
MODEL TTS 26 B
PULSE SIGNALING TEST SET
ISSUE 2
NORTHEAST ELECTRONICS CORPORATION
P. 0. BOX 649 - CONCORD, N. H. 03301

PROPRIETARY NOTICE
The information contained in this publication is the
of Northeast Electronics Corporation and may not be reproduced
or used for manufacturing purposes or disclosed to third parties
without the written permission of Northeast Electronics Corpor-
ation.
WARRANTY
NEC warrants all products manufactured or sold by NEC to
be free from defects in materials and workmanship, subject to
the following terms and provisions.
NECts obligations under this warranty are limited to repair-.
ing, adjusting, or replacing at our option, with reasonable prompt-
ness, any NEC product which shall
within twelve (12) months after
delivery to the original purchaser, and after normal and proper us
-
age, prove to be defective on NEC inspection, provided that the
purchaser shall have reasonably inspected products when received
and notified NEC of any apparent defects discovered
within fifteen
(15) days of receipt of shipment. NEC shall not be liable for any
manufacturing costs of the buyer, lost profits or good
will of the
buyer, or any other special or consequential damages sustained
or expenses incurred
by the buyer by reason of the ilse or sale
of any defective NEC product.
No products may be returned to NEC except
with our written
permission. After receiving NEC factory authorization, material
requiring repair
or replacement should be sent prepaid to the fac-
tory accompanied by a written statement setting forth as comphte-
ly ae possible the defects and the conditions under which they occur-
red. Material delivered by NEC shall not be considered defective
if it satisfactorily Wills the buyer's performance requirements
and/or is in accordance wi%-approvedsamples. NEC8sobligations
on performance of products delivered shall be limited to comply-
ing with specifications accompanying a purchase order or dth pub-
lished epecifications on standard catalog items. This warranty does
not extend
to any NEC products which have been subject to misuse,
neglect, accidents or improper installation or applications, nor
shall it extend to units which have been repaired or substantially
altered outside the NEC factory, nor to any associated instruments
,
equipment6 or apparatus. This warranty is in lieu of all other war-
ranties, express or implied.

TTS 26B
Section
1
2
3
4
5
6
Figure
3-1
3
-2
3-3
3-3a
3-3b
3-3c
TABLE OF CONTENTS
Title
GENERAL DESCRIPTION
SPECIFICATIONS
OPERATING INSTRUCTIONS
CIRCUIT DESCRIPTION
MAINTENANCE
ELECTRONIC PARTS LIST
LIST OF ILLUSTRATIONS
Title
Front Panel Controls
Send Circuits
Receive Circuits
Meter Circuit
Meter Circuit
Meter Circuit
Supervisor Monitor Circuits
TTS 26B Block Diagram
TTS 26B Schematic Diagram
Component Location
E95075
Component Location E95026
Page
1 - 1
2-1
3-1
4- 1
5-1
6-1
Page
2 -2
3-8
3
- 10
3-12
3
- 16
3-18
3-23

TTS 26B
SECTION 1
Section 1
1.1
GENERAL.
1.2 The Model
TTS 26B is a compact pulse sig-
naling test set designed to send pulses generated
by either a built-in. transistorized oscillator or an
external source, and to measure the
'36 break and
speed of the transmitted pulses, or of pulses
received from external sources. The
70 break of
the pulses transmitted by the instrument can be
varied over a wide range. The speed of these
pulses can be varied in seven discrete steps.
1.
3
Signals can be received or transmitted on a
loopor an
E&M basis. A seriesof jacks isprovided
for the proper connection to the particular circuit
to be tested. Switches and keys permit the test-
man to set up testing circuits for different combin-
ations of sending and receiving on the basis of
loop,
E&M, or a combination of both signaling
sys
terns.
1.4 The Model TTS 26B may be used as a pulse
repeater or converter. Signals from
an external
circuit may be applied to the EXT
DIAL jack or
terminals and used to operate the internal pulsing
relay. The
OJo break of this output signal can be
varied, and it can be retransmitted on a loop or
an %&M basis. It can be used to control external
circuits such as voice-frequency signaling circuits,
polar duplex circuits, etc.
1.
5 Measurements may be made by connecting
the high impedance meter circuit to the circuit
under test either directly or through a low imped-
ance "slave" relay. The meter slave relay
is
particularly useful when testing circuits which
have high capacitance or inductance. Such circuits
might distort the pulse wave shape and thereby
result in erroneous meter readings if the high
impedance meter were used directly on the cir
-
cuit under test.
1.6 The meter has
two scales - one for measur-
ing
OJo break and the other for pulse speed mea-
surements in pulses per second
(PPS).
The
correct scale is obtained
by switching the meter
circuit to correspond to the selected mode of
operation.
1.7 The TTS
26B may be operated from the
48-volt central office battery or from
a suitable
substitute such
as an NEC PSI01 - In emergen-
cies a heavy duty 45-volt dry cell will supply
adequate power to the instrument for a shorttime.
1. 8 The set is contained in an aluminum carrying
case with a removable, hinged cover which inclu-
des
a storage compartment for cords, small
tools, and such items.
1.9 Accessory covers are available to provide
additional functions which increase the versatility
of the Model TTS
26B. These can be substituted
for, or ordered in place of, the removable cover
which normally
is supplied with the set.
A
separate description of each of the cover acces-
sories is supplied as supplementary information.
1.
10 A relay rack mounted version of the TTS 26B
is available in the form of the TTS 26BDR.

TTS 26B
SECTION
2
SPECIFICATIONS
2.1 GENERAL.
Section
2
2. 2 Table 2- 1 Lists the specifications of the TTS 26B
TABLE
2-1
METER
Ranges
70 Break: 070 to 100'70
Speed: 0 to 25 pps
Scales
O/o Break: 170divisions
Speed
: 1 pps divisions
. -
IMPEDANCE OF MEASURING CIRCUITS
Meter Circuit: Approx. 7,50052
Meter Relay: Approx. 40052
FOR SPEED MEASUREMENTS
Approx. 4,30052
SEND SIGNALS
- Internal Oscillator: 4,6,8,10,12,
14,20 ~ulses/~ec.One addi-
tional frequency can
be installed
on special order.
External Dial:
A standarddialor20pps
dial may be used to generate
pulses
.
'% Break Range: At least 12%to 8570
Transit time <1 millisec.
CONTROLS
ADJ
yo BREAK
METER CAL
METER CIRCUIT Switch
FUNCTION Switch
PULSES PER SEC Switch
RECEIVE Switch
SEND Switch
EXT DIAL CIRCUIT Switch
SEND and TEST Key Switch
TWD-L Key Switch
TWD-D Key Switch
SEND Turnbutton Switch
SPARK
SUP Turnbutton Switch
DROP
E =G&O M -B&O
DROP E =G&B M =B&O
Toggle Switch
JACKS
1. EXT DIAL
2. SEND RELAY
3. SEND 1 (LOOP)
4. SEND
2 (LOOP)
5. SEND B&G
6. REG LOOP
7. REC E&M
8. E
9. M
10. LINE
11. DROP
12. 48VoltS(-) T(+)
13. 48 Volt S (t) T (-)
14. EXT ADAPT (FOR ACCESSORIES)
15. DROP
E =G&O M =B&O
DROP E =G&B M =B&O
SUPERVISORY LAMPS
LINE (E)
DROP
(M)
POWER REQUIREMENTS
48 volts
DC, 220mA
Operable from approx. 40V to 55V
Diode protection for polarity reversal.
24 volt DC operation available on
special order.
SIZE
14"w x 10"h x 8"d (includes cover)
WEIGHT
1 5 pounds
RACK MOUNTED EQUIPMENT
The Model TTS 26B is also available
for bay mounting; it is called Model
TTS 26BDR. It includes a telephone
dial as well as all the features of the
portable set.
Any of the accessories available
for the cover of the TTS 26B can be
supplied on panels for bay mounting.
Ordering information will be supplied
on request.

TTS 26B
Section 2
Figure 3-1. Front Panel Controls

TTS 26B Section
3
SECTION 3
OPERATING INSTRUCTIONS
- 3.1 GENERAL.
--
3.2
Table 3-1 lists the functions of all controls and indicators shown indexed on fig. 3-1.
Paragraphs
3.3 through 3. 19 provide the operating instructions.
TABLE 3-1
Index No. Control or
Indicator Function
SEND PPS Switch
- Provides the following functions:
1. Switches the power on or off.
2. Controls the pulse rate of the internal oscillator for
any one of the available seven discrete pulse rates.
ADJ
70 BREAK Provides the means for adjusting the
70 break of the
POTENTIOMETER transmitted pulses from the internal oscillator or from
an external dial.
METER CAL Provides the means for calibrating the meter circuitry.
POTENTIOMETER
FUNCTION SWITCH Provides the following functions in clockwise sequence:
1. SEND a. ON HOOK
b. OFF HOOK
2. SEND AND
REC
L
I
'8
3. CAL a. ADJ 170 BREAK
\
b. CAL METER
RECEIVE Switch Provides the following receive functions in clockwise
sequence:
1. B&G ON LOOP
2. LOOP
3. B&O (M)
5. G&O(E)
6.
The final clockwise position permits the SEND or SENE
AND REC switch to control both sending and receiving
functions, as shown in item
6 following.

Section 3
TTS 26B
TABLE 3-1
Index No. Control or Function
SEND or SEND AND Provides the following,sending modes in clockwise sequence,
RECEIVE switch when the receive switch is in final clockwise position:
1. SEND LOOP, REC G&B .
2. SEND LOOP, REC LOOP
3. E&M LINE B &G on M
DROP G&Oon E
4. E&M LINE B&Oon M (See Note 1)
NOTE 1: The
E lead status in this mode is controlled by
the DROP toggle switch.
NOTE: The two SEND LOOP positions provide identical
sending conditions; only the receiving functions
are different in these positfons when this switch
.
is used to control both sending and receiving
functions.
METER CIRCUIT Provides the following measuring functions inclockwise
switch sequence:
1. 0-25 PPS (Pulse Speed)
2. 70 BREAK DIRECT
3. 70 BREAK T-HRUMETER RELAY
EXT DIAL CIRCUIT Provides the following modes of operation of the external
switch dial circuit in clockwise sequence:
1. TALK
2. DIAL RELAY B&G
3. DIAL RELAY a. LOOP
b. M
c. E
FUNCTION key switch Provides the following functions:
1. TEST L&D(operated upward) This position disconnects
the LINE and DROP, and the
E and M jacks from access to
other circuits of the set. The LINE (E) and DROP (M) lamp
relays are bridged on, and the LINE and DROP jacks are
connected together tip to tip and ring.to ring.
2. SEND DIAL (position normal)
3. SEND OSC (operated downward)

TTS 26B
Section 3
TABLE 3-1
Index No. Control or Function
Indicator
10 LINE
(E) key switch Provides for the connection of the following supervisory
and measurement functions toward the line:
1. ON HOOK (operatedupward)
2. MONITOR (norma1 position)
3. OFF HOOK (operated downward)
DROP (M)key switch Provides for the connection of the following supervisory
and measurement functions toward the line:
1. ON HOOK (operatedupward)
2. MONITOR (nor
ma1 position)
3. OFF HOOK (operated downward)
SEND turnbutton switch Provides the following SENDfunctions on the LOOP SIGNAL-
ING jacks SEND 1 and SEND
2:
1. SEND RT ON 1&2(operated clockwise)
2.
SEND SLEEVES (operated counter clockwise)
In normal use this switch should be in the SEND RT
ON 1&2
position. The pricipal use for the SEND SLEEVE position
is for special applications where direct access to the SEN1
relay armature, make, and break contacts is desired
SPARK
SUP turnbutton Inserts an internal spark suppression circuit across the
switch SEND RELAY CONTACTS.
DROP toggle switch Determines the sending status of the
E lead, either ground
and open or ground and battery.
Jacks The following 310-type jacks are provided from left to right:
1.
EXT DIAL (for connecting an external dial, pulsing
source, or a telephone set)
2. SEND RELAY (fordirectconnectionto the relaycontacts)
3. LOOP SIGNALING
- SEND 1
4. LOOP SIGNALING - SEND 2
5. LOOP SIGNALING - SEND B&G
6. LOOP SIGNALING - REC LOOP
7.
EAND M SIGNALING - REC E&M
r

TTS 26B
Section 3
TABLE 3-1
Index No. Control or Function
Indicator
15 (cont) Jacks
TERMINALS
LAMPS
18 METER
8.
E AND M SIGNALING - E (for connection to the E lead)
9.
E AND M SIGNALING - M (for connection to the M lead)
10. E AND M SIGNALING - LINE
11. E
AND M SIGNALING - DROP
12- 48 VOLT, S =BATT, T =GND
The following terminals are provided:
1. EXT ADAPT Connector
- Provides for connection to
accessory covers (Located in upper left of panel).
2.
EXT DIAL Binding Posts (2) - Provides for connection
of an external dial, source of pulses, or of a telephone
set (located in upper left of panel).
3.
GND Binding Posts - Provides access to the TTS 26B
ground.
Two supervisory lamps, designated
LINE (E) and DROP (M)
are provided to indicate a busy (lampdark) or
idle condition
(lamps lighted) an the line and drop circuits to which the
'
set is connected, when E and M supervision is present on
the circuits.
Provides a display for all measurements.