HP TM 11-6625-2779-14&P manual Front, Side and Rear Pane

Model 3555B

Section III

Table 3-1. Front, Side and Rear Pane

(1)

S and G Jacks:

Binding posts accepting banana

Controls, Indicators and Connectors either the

plugs, spade lugs, phone tips or bare wires for

NOISE BRDG or the NOISE TERM before the

connection to the case ground (G) and sleeves (S)

NOISE WTG filters can be selected.

of all INPUT jacks (12) and DIAL/AC MON jacks

(9) FUNCTION

Switch:

A

series

of

interlocking

(10) and (11).

pushbutton switches (with the exception of the

(2)

Shorting

Strap:

A swing-away shorting strap

HOLD switch which is push-push type) with the

connecting the S and G terminals together which

following functions:

may be used to isolate the jack sleeves from case

a.

VF/Nm

ground. Not for use with type 347 plugs.

1. HOLD:

Applies

a

dc

holding bridge

(3)

WTG Switch:

Selects

weighting

filters for

noise

across the metallic line for the NG, 900

measurements.

These filters are selectable only

and

600

functions.

The

HOLD

when the INPUT switch is in one of the two NOISE

pushbutton is the push-push type, ie,

positions.

The 3kHz FLAT, C-MSG, 15kHz FLAT

push to make and push to break. The

and PROG filters all conform to the standards set

HOLD

function

cannot

be

up by the Bell System and Edison Institute for

accomplished when any one of the

measuring message circuit noise.

CARRIER pushbuttons is depressed.

(4)

RANGE SWITCH: Selects dBm or dBm ranges of

2. DIAL/BAT:

Connects

the

multiple

input sensitivity.

The

RANGE

switch markings

INPUT jacks in parallel with the

correspond to the 0 markings on the meter scale

DIAL/AC MON jacks for the dial and

(6). The black markings are dBm for transmission

talk operation.

The circuit is arranged

measurements and the blue markings are dBrn for

for loop dialing and the line under test

noise measurements.

must supply talk battery. Connects the

(5)

RESPONSE

Switch:

Selects

NORM

meter

meter circuit and a load to the internal

response for transmission level measurements or

power supply to check the condition of

DAMP for noise measurements where noise is

the battery, ac power or external office

impulsive in nature.

battery as indicated on the green meter

(6)

Meter:

A taut band individually calibrated meter

scale. POWER (7) must be ON for the

with shaped pole pieces to provide a linear dBm

battery test.

indication with equal accuracy and resolution over

3. NG:

Selects the noise-to-ground input

the entire meter scale.

The dBm scale is marked

circuits

for

measuring

longitudinal

in black and has 0.1dB resolution for transmission

noise.

Attenuation of 40dB is inserted

measurements.

The 0 marking at the right end of

by this circuit. Earth ground should be

the scale corresponds to the black RANGE switch

connected to the black G binding post

setting. The dBm scale is marked in blue for noise

(1)

measurements.

The 0 marking at the left end of

4. 900:

Selects

the

input

circuitry

for

the scale corresponds to the blue RANGE switch

balanced

900 ohm

circuits.

This

setting.

The

green

arc

marked BAT GOOD

function selects a low frequency

corresponds to the green DIAL BAT pushbutton for

transformer for

voice

frequencies.

checking the power source.

The left edge of the

Response of this transformer is 20Hz

arc corresponds to the battery cut-off voltage of 24

to 20kHz.

volts and the right edge (meter full-scale)

5.

600:

Selects

the

input

circuitry

for

represents 60 volts which is the maximum voltage

balanced

600

ohm

circuits.

A

low

that can be used to power the set without internal

frequency

transformer

is selected

for

damage.

this function.

(7)

POWER ON/OFF Switch: turns on all power to the

b.

Carrier

set. The set operates from either 115 volts or 230

1.

600:

Selects

the

input

circuitry

for

volts ac, the internal 45 volt dry cell battery or from

balanced

600

ohm

circuits.

A high

an external office battery supply.

frequency transformer is selected for

(8)

INPUT

Switch:

Selects TMS, either BRDG or

this

function.

Response

of

this

TERM for transmission measurements and NOISE,

transformer is 1kHz to 600kHz.

The

either BRDG or TERM for noise measurements.

HOLD function is not operative in any

For noise

measurements the switch must

be in

of the carrier functions.

3-3