ACCURATE ELECTRONICS 104003C Manual - Página 2

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ACCURATE ELECTRONICS INC

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FIGURE 3. Hypothetical Circuit Employing 104003C Line Amplifiers

off-premise-extension (OPX) circuit in which 104003C Line Amplifiers are

used in a variety of typical applications.

LEVELS

2.02 Levels in both the transmit and the receive channel are individually set

to provide up to 24dB of either flat gain or flat loss in 0.1dB increments.

Front panel switches allow either gain or loss to be introduced into either

channel independently. Maximum output of either channel is +7dBm, with

less than 1% distortion.

EQUALIZATION

2.03 Active slope equalization is provided in both the transmit and the

receive channel of the 104003C. Use of the module's equalizers in one or

both channels is dependent upon the module's position in the circuit.

Equalizing at the receive end of the circuit (post-equalization) is generally

preferable to equalizing at the transmit end (pre-equalization).

equalization tends to amplify high-frequency signals to a level that is

conducive to crosstalk. Post-equalization not only eliminates this problem

but also expedites the equalization process because the circuit is easier to

equalize at the receive end. In some applications, pre-equalization may be

necessary.

Use of the 104003C as a bi-directional amplifier at an

intermediate point in a 4wire circuit, for example, often requires the use of

the transmit-channel equalizer as well as the receive-channel equalizer.

2.04 Up to 7.75dB of slope equalization (1000 to 3000hz) in 0.25dB

increments is provided in both the transmit and the receive channel to

compensate for the frequency-response characteristics of loaded and

nonloaded telephone cable. Equalized gain is independently switch-optioned

into both channels via DIP switches on the module's front panel. The

module's equalized gain response is designed to provide frequency response

within + 1dB over the frequency range of 300 to 3000Hz when used with any

combination of nonloaded cable. The equalized gain response is not

affected by the flat gain (or loss) adjustments, which are used to provide

precise transmission levels.

IMPEDANCE MATCHING

2.05 Impedance-matching transformers at the facility and terminal ports may

be independently switch-optioned for balanced 1200, 600, or 150-ohm

terminating impedance. This allows the 104003C to interface loaded cable

(1200 ohms), nonloaded cable (600 or 150 ohms), carrier, SX signaling units,

terminating sets, or station apparatus (600 ohms). The 150-ohm option is

primarily used to provide a small amount of equalization for short segments

of nonloaded cable.

FIGURE 4. 4Wire Circuit Employing DX signaling

This document contains proprietary information and is supplied for identification, maintenance, engineering evaluation or inspection purposes only and shall not be duplicated or disclosed without written

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Practice Section 104003C Rev A

BEAVERTON OR USA 503.641.0118

2.06 All four impedance-matching transformers on the 104003C are center-

tapped to derive simplex leads, allowing this module to be applied to circuits

employing DX, loopback, or other dc signaling schemes (Figure 4).

LOOPBACK

2.07 The loopback feature of the 104003C allows remote testing of the levels

and frequency response of the facility. Data set disable leads (TEK5 and

TEK6) are provided to electrically disable an associated data set during

loopback. Loopback may be tone or dc activated.

2.08 In the tone-activated mode, any 1 of 11 loopback-activation frequencies

may be selected via switch option. Loopback is activated by placing the

selected loopback tone on the module's receive pair for longer than 1.4

seconds and then removing that tone. The 1040003C initiates loopback only

upon removal of the tone and remains looped until the selected loopback tone

is reapplied to the module's receive pair for longer than 0.7 second. The

Pre-

switch-selectable loopback-tone frequency option permits up to eleven

104003C modules (when connected in a bridging arrangement) to be

individually tested from a central bridging location.

2.09 The module responds to minimum loop-back levels of –18dBm (with

receive-channel gain at zero). Gain or loss adjustments in the receive channel

will directly increase or decrease the minimum loopback sensitivity on a dB-

for-dB basis. The center-frequency stability of each loopback tone is + 0.2%;

maximum bandwidth is 75Hz.

frequency-selection option combine to prevent inadvertent loopback.

2.10 Loopback levels of +16, +9, -16, or –23dB may be prescription-set via

two-position DIP switch S4. This option permits loopback levels to be

coordinated with various TLP's. Standard data TLP's (-3 receive, +13

transmit) require 16dB of gain to provide the 0dB loopback level, Federal

Aviation Agency (F.A.A) data TLP's (-9 receive, 0 transmit) require 9dB of

gain, inverted data TLP's (+13, receive, -3 transmit) require 16dB of loss,

and conventional voice TLP's (+7 receive, -16 transmit) require 23dB of loss.

Once loopback levels are properly set, equal-level loopback (i.e., test tone

received equals test tone sent [+1dB], referenced to appropriate TLP's) will

result.

2.11 In the dc-activated mode, loopback is accomplished through use of a

manually operated local key or switch or by manually applying a ground

potential to pin 1 of the 104003C's 56-pin connector. The module remains

in loopback until the ground potential is removed.

2.12 Common pin assignments allow the 104003C to be interchanged with

other 10400X-series Line Amps or with 4412-series Data Station

Termination modules. While a 4412-series module is normally used in data

termination applications, a 104003C may, in rare cases, also be used. In data

applications, auxiliary relay contacts on the 104003C may be used to disable

an associated data set during loopback operation or to light an external

loopback lamp.

3. INSTALLATION

3.01

The 104003C Line Amplifier with Loopback should be visually

inspected upon arrival in order to find possible damage incurred during

shipment. If damage is noted, a claim should immediately be filed with the

carrier. If stored, the module should be visually inspected again prior to

installation.

January 2014

FAX 503.646.3903

A 3dB signal-to-guard ratio and the