ACCURATE ELECTRONICS 104001C User manual

Page 1 of 10
Model 104001C
January 2014
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
permission of: ACCURATE ELECTRONICS INC By accepting this document the recipient agrees to make every effort to prevent unauthorized use of this information.
Prac_104001C0_RevB.pdf
Contents:
Section 1. General 1
Section 2. Application 2
Section 3. Installation 4
Section 4. Circuit Description 7
Section 5. Mechanical Outline 7
Section 6. Specifications 7
Section 7. Testing and Troubleshooting 8
Section 8. Maintenance 8
Section 9. Warranty 8
Figure 1. Circuit Description 9
Figure 2. Mechanical Outline 10
Figure 3. Typical Off-Premise-Station (OPS)
Circuit Using 104001C Line Amplifiers 2
Figure 4. Module Arrangement for Two
4Wire 6Way Resistive Bridges in an
Accurate 246 Mounting Assembly 2
Figure 5. Typical 4Wire DX Signaling
Application Using 104001C
Line Amplifiers 2
Figure 6. 4000C 1 Option Switch and
Strap Locations 4
Table 1. Typical Transmit and Receive
Equalization Frequency Response 3
Table 2. Terminating Impedance Selection
Guidelines 3
Table 3. Externals Connections to 104001C 4
Table 4. Equalized Gain Settings From
Cable Loss Data 7
Table 5. Test Guide Checklist 9
1. GENERAL
1.01 This practice provides application, specification, circuit and mechanical
description, maintenance, installation, and warranty information relating to
Accurate Electronics’ Prescription Line Amplifier, Model 104001C.
1.02 The 104001C Prescription Line Amplifier module ( Figure 1) provides
active prescription level control, active prescription amplitude equalization,
and impedance matching for the transmit and receive channels of a 4wire
voice-frequency transmission facility. The 104001C also contains two
independent sealing-current sources, one on the facility side and the other on
the terminal side of the module.
Note: Because the 104001C has identical equalizers in both cannels,
identical impedance-matching capabilities at all four ports, and identical
sealing-current sources on the facility and terminal sides, it can be used
either at an intermediate point or near an end point of a 4wire facility.
Although the terms “facility side” and “terminal side” do not strictly apply
in intermediate applications, these terms will for convenience, be used
throughout this practice as follows: Facility side will refer to the receive-
input, transmit-output side of the 104001C, and Terminal side will refer to
the transmit-input, receive-output side as shown in Figure 1. of this practice.
1.03 This practice section is reissued to cover the Issue 4 version of the
104001C module (Accurate Electronic part number 104001C). The Issue 4
Module is identical to its Issue 3 predecessor except for the addition of a
front-panel power-on indicator LED.
1.04 The 4001C’s transmit and receive amplifiers can be independently
prescription-set to provide from 0 to 24dB of loss or 0 to 24dB of gain in
their respective channels. For each channel, gain or loss is selected via a
front-panel slide switch. The desired amount of gain or loss is then
introduced into each channel in precise 0.1dB increments via a front-panel
DIP switch. The maximum output level of each channel is +10dBm, with
distortion at maximum output less than 1 percent.
1.05 All four ports of the 104001C module can be switch-optioned for
balanced 1200, 600, or 150-ohm terminating impedance. The impedance of
the two facility-side ports is selected independently from that of the two
terminal-side ports. The transformers at all four ports of the module are
center-tapped to derive balanced simplex leads.
1.06 In addition to active prescription level-control circuitry, the 104001C
contains active prescription slope-type amplitude-equalization circuitry in
both channels. The transmit and receive equalizers are identical, each
providing from 0 to 7.5dB of gain at 2804Hz (re 1004Hz). Equalization is
introduced into each channel independently, in 0.5dB increments, via DIP
switches on the module’s front panel.
1.07 The 104001C can be optioned to provide 25mA of internally generated
sealing current to metallic facilities on the facility and terminal sides of the
module, to accept externally generated sealing current from the far ends of
the facilities on both sides of the module, to derive normal simplex leads on
both sides of the module, or to provide bypassed (straight-through) simplex-
lead signaling via a path separate from the transmit and receive transmission
paths. Each of the 104001C’s two internal sealing-current sources has a
“ZAP” feature by which a greater amount of sealing current is provided for a
few seconds when power is initially applied to the module.
1.08 The front panel of the 104001C is designed so that all level and
equalization adjustments can be made while the module is mounted in place.
Six front-panel bantam-type test jacks facilitate alignment and maintenance.
Both bridging and opening jacks are provided at the facility-side ports;
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Practice Section 10model Rev B
PRESCRIPTION LINE AMPLIFIER
MODEL 104001C

ACCURATE ELECTRONICS INC Practice Section 104001C Rev B January 2014
WWW.ACCURATE.ORG PO BOX 1654 97075-1654 8687 SW HALL BLVD 97008 BEAVERTON OR USA 503.641.0118 FAX [phone]
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
permission of: ACCURATE ELECTRONICS INC By accepting this document the recipient agrees to make every effort to prevent unauthorized use of this information.
2
opening jacks alone are provided at the terminal side ports. Front-panel
“SEAL CURR 1” and “SEAL CURR 2” LED’s light when the module’s
internal facility-side and terminal-side sealing-current options, respectively,
are activated and sealing current is flowing. Also located on the front-panel
is a “PWR ON” LED that lights when power is applied to the module.
1.09 An internally regulated power supply permits the module to operate on
filtered, ground-referenced –22 to –56VDC input. If the internal sealing
current optioned is selected, input power must be from –42 to –56VDC.
Maximum current requirements (at –48VDC inputs) are as follows:
With both sealing-current sources inactive, 30mA at idle and
65mA at maximum transmit and receive output levels.
With one sealing-current source active, 57mA at idle and 92mA
at maximum output levels.
With both sealing-current sources active, 84mA at idle and
132mA at maximum output levels.
1.10 Surge protection isprovided for the input and output of the transmit and
receive amplifiers. Reverse-battery protection and transient limiting are
provided for the module’s internal power-supply circuitry.
1.11 A Type-10 module, the 104001C mounts in one-position of an Accurate
Electronic Type-10 Mounting Shelf, versions of which are available for
relay-rack or apparatus-case installation. In relay-rack applications, up to 12
modules can be mounted across a 19-inch rack, while up to 14 modules can
be mounted across a 23-inch rack. The 104001C can also be used in the
Accurate 246 Resistive Data Bridge System, in which case the module
mounts in one position of the Accurate 246 Mounting Assembly. The 246
Assembly, basically a prewired Type-10 Shelf equipped with a connectorized
printed-circuit back-plane, houses up to 12 modules and mounts in a 19-inch
relay rack. The 246 Assembly and all rack-configured Type-10 Shelves each
occupy 6 inches of vertical rack space.
2. APPLICATION
2.01 The 104001C Prescription Line Amplifier with sealing current is
designed for use on 4wire voice-frequency transmission facilities, where it
provides active prescription level control, active prescription amplitude
equalization, and impedance matching in both the transmit and receive
channels. The module also contributes longitudinal isolation and surge
protection for the facility. In itself, the 104001C module is equivalent to a
4wire-to-4wire (44V4) voice-frequency repeater. When used with an
Accurate 420X Terminating Set (or equivalent), a 2wire-to-4wire (24V4)
repeater results.
2.02 Because equalization is available in both channels (instead of in the
receive channel only), the 104001C can be used not only as a terminal
repeater but also as an intermediate repeater. Figure 3 shows a typical off-
premises-station (OPS) circuit in which the 104001C is used in a variety of
applications.
2.03 The 104001C can also be used in the Accurate 246 Resistive Data
Bridge System, where each module provides an active interface between an
external 4wire facility and the passive fixed-loss data bridge. Figure 4 shows
a typical configuration for two 4wire 6way fixed-loss data bridges.
Level Control
2.04 Prescription level-control circuitry allows from 0 to 24dB of gain or
loss to be introduced into each channel of the 104001C independently. For
each channel, either flat gain or flat loss is selected via a front-panel slide
FIGURE 5. Typical 4Wire DX Signaling Application Using 104001C Line Amplifiers.
FIGURE 4. Module Arrangement for two (2) 4Wire 6Way Resistive
Bridges in a n Accurate 246 Mounting Assembly.
FIGURE 3. Typical Off-Premises-Station (OPS) Circuit using 104001C Line Amplifiers.

ACCURATE ELECTRONICS INC Practice Section 104001C Rev B January 2014
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permission of: ACCURATE ELECTRONICS INC By accepting this document the recipient agrees to make every effort to prevent unauthorized use of this information.
3
switch. The precise amount of gain or loss required in the channel is then
selected in 0.1dB increments, via an eight-position front-panel DIP switch.
Amplitude Equalization
2.05 The 104001C’s active slope-type amplitude equalizers allow from 0 to
7.5dB of prescription-set gain at 2804Hz (re 1004Hz) to be introduced into
the module’s receive and transmit channels individually. Adjustable in 0.5dB
increments via front-panel DIP switches, this type of equalization is ideal for
nonloaded cable and can also be used effectively in many loaded-cable
applications to compensate for the frequency-response characteristics of
metallic facilities interfacing the module. The equalized gain response of
each module is not affected by flat gain or loss adjustments, which are used
to provide precise transmission alignment. The frequency response of the
equalizers is shown in tabular format in Table 1.
Note: Because introduction of equalization into either channel of the
104001C does not affect 1004Hz levels, equalization can be introduced not
only before but after transmission levels are set.
2.06 Whether one or both channels’ equalizers are used depends upon the
104001C’s position in the circuit. Use of the module as an amplifier at an
intermediate point in a 4wire circuit, for example, often requires the use of
the transmit equalizer as well as the receive equalizer. In any case, equalizing
at the receive end of a circuit (post-equalization) is generally preferable to
equalizing at the transmit end (pre-equalization). Pre-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, however, pre-equalization may be necessary
because post-equalization at the receive end is unavailable.
Impedance Matching
2.07 Impedance-matching transformers at all four ports of the 104001C can
be switch-optioned for balanced 1200, 600, or 150-ohm terminating
impedance. A single option switch selects the desired impedance for both
facility-side ports (receive input and transmit output); a second option switch
performs this function for both terminal-side ports (receive output and
transmit input). Thus, on both the facility and terminal sides, the 104001C
can interface a variety of facilities and equipment, as listed in Table 2. The
150-ohm options provide a small amount of slope equalization for long
sections of non-loaded cable through the deliberate impedance mismatch.
TABLE 2. Terminating Impedance Selection Guidelines.
Impedance
Facility or Equipment Guidelines
1200 ohms
Loaded Cable
600 ohms
Non-loaded cable, carrier, SF and DX signaling
units, terminating sets, station apparatus.
Sealing Current and Simplex Leads
2.08 The 104001C contains two separate and independent 25mA sealing-
current sources, one on the facility side and one on the terminal side of the
module. In addition, all four impedance-matching transformers on the
104001C are center-tapped to derive balanced simplex (SX) leads. Option
switches on the facility and terminal sides of the module afford a choice of
four sealing-current and simplex-lead options, as follows:
2.09 When the 104001C’s internal sealing-current option on the facility side
is selected, 25mA of sealing current flows from the transmit output port (pins
41 and 47) and returns via the receive input port (pins 7 and 13). When the
4001C’s internal sealing-current option on the terminal side is selected,
25mA of sealing current flows from the transmit input port (pins 55 and 49)
and returns via the receive output port (pins 5 and 15). Both sealing-current
sources have a ZAP feature that provides a greater amount of current for a
few seconds when power is initially applied to the module. Each of the two
front-panel “SEAL CURR” LEDs lights when its respective source is active
and current is flowing.
2.10 A second sealing-current/simplex-lead option available independently
on the facility and terminal sides of the 104001C excludes the module’s
sealing-current sources from the circuit and provides return paths for sealing
current applied at the distant end of the facilities.
2.11 A third option is the derivation of normal simplex leads on either or
both sides of the module. This allows the 104001C to be used on circuits
TABLE 1. Typical Transmit and Receive Equalization Frequency Response
Receive
Equalizer
Switch
Setting
(dB)
Equalized Gain (dB) Introduced at Various Frequencies
300Hz
400Hz
500Hz
800Hz
1004Hz
1500Hz
1800Hz
2500Hz
2804Hz
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
0.0
-0.23
-0.52
-0.75
-1.00
-1.22
-1.50
-1.71
-2.02
-2.25
-2.49
-2.68
-2.89
-3.07
-3.29
-3.45
0.0
-0.19
-0.42
-0.60
-0.80
-0.98
-1.20
-1.37
-1.63
-1.79
-1.98
-2.14
-2.30
-2.44
-2.61
-2.74
0.0
-0.15
-0.33
-0.49
-0.64
-0.78
-0.95
-1.09
-1.29
-1.42
-1.57
-1.69
-1.81
-1.93
-2.05
-2.15
0.0
-0.06
-0.13
-0.18
-0.24
-0.29
-0.36
-0.41
-0.49
-0.53
-0.59
-0.63
-0.68
-0.72
-0.76
-0.78
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
+0.15
+0.32
+0.46
+0.61
+0.75
+0.90
+1.03
+1.22
+1.33
+1.47
+1.58
+1.69
+1.79
+1.89
+1.98
0.0
+0.43
+0.93
+1.33
+1.76
+2.15
+2.60
+2.97
+3.54
+3.90
+4.32
+4.67
+5.05
+5.38
+5.76
+6.06
0.0
+0.43
+0.93
+1.33
+1.76
+2.15
+2.60
+2.97
+3.54
+3.90
+4.32
+4.67
+5.05
+5.38
+5.76
+6.06
0.0
+0.50
+1.07
+1.54
+2.04
+2.49
+3.01
+3.45
+4.12
+4.56
+5.08
+5.51
+5.99
+6.41
+6.90
+7.30

ACCURATE ELECTRONICS INC Practice Section 104001C Rev B January 2014
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4
employing DX, loop back or other dc signaling schemes (see Figure 4).
Normal simplex leads can also be used to apply sealing current to a metallic
facility from a local source external to the module.
2.12 The fourth sealing-current/simplex-lead option is bypassed simplex-
lead signaling. This option provides a straight-through simplex-lead
signaling path between the module’s facility and terminal sides that is
completely separate from the modules’transmit and receive transmission
paths. A switch option available when bypassed simplex-lead signaling is
selected provides either a normal straight-through signaling path (RCV IN
SX to RCV OUT SX and XMT IN SX to XMT OUT SX) or a reversed
straight-through signaling path (RCV IN SX to XMT IN SX and RCV OUT
SX to XMT OUT SX). The reversed signaling-path option is used to
compensate for polarity reversals in duplex- (DX-) signaling and ground-start
application.
3. INSTALLATION
Inspection
3.01 The 104001C Prescription Line Amplifier module should be visually
inspected upon arrival 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.
Mounting
3.02 The 104001C module mounts in one position of an Accurate Type-10
Mounting Shelf, which is available in configurations for relay-rack and
apparatus-case installation, or in one position of an Accurate 246 Resistive
Data Bridge Mounting Assembly. The module plugs physically and
electrically into a 56-pin connector at the rear of its shelf or assembly
position.
Installer Connections
3.03 Before making any connections to the mounting shelf or assembly,
ensure that power is off and modules are removed. Modules should be put
into place only after they are properly optioned and after wiring is completed.
When installing 104001C modules in 246 Assemblies, refer to the Accurate
practice on the 246 Resistive Data Bridge System for cabling instructions and
module pinout assignments.
3.04 Table 3 lists external connections to the 104001C module. All
connections are made via wire wrapping to the 56-pin connector at the rear
of the module’s mounting shelf position. Pin numbers are found on the body
of the connector.
TABLE 3. External Connections to 104001C.
CONNECT
To PIN
XMT OUT TIP
41
XMT OUT RING
47
XMT OUT SIMPLEX
43 and 45
RCV IN TIP
7
RCV IN RING
13
RCV IN SIMPLEX
9 and 11
XMT IN TIP
55
XMT IN RING
49
XMT IN SIMPLEX
51 and 53
RCV OUT TIP
5
RCV OUT RING
15
RCV OUT SIMPLEX
1 and 3
-BATT (FILTERED -22 TO -56
VDC IN)
35
Strap Options
3.05 As shipped from Accurate, connector pin 43 is the 104001C’s XMT
OUT SX lead and connector pin 3 is the RCV OUT SX lead. If an additional
(or alternative) connector-pin appearance for the XMT OUT SX lead is
desired on pin 45, install option strap JP9 where indicated on the module’s
printed circuit board, as shown in Figure 6. If an additional (or alternative)
connector-pin appearance for the RCV OUT SX lead is desired on pin 1,
install option strap JP10 where indicated on the module’s printed circuit
board (also shown in Figure 6). Before installing JP9 or JP10, be sure to
observe the caution below.
Switch Options
3.06 Five option switches must be set before the 104001C can be placed into
service. Locations of these switches on the module’s printed circuit board
are shown in Figure 6, and instructions for setting the switches are given in
paragraphs 3.07 and 3.08.
CAUTION: Extreme care must be taken when soldering on printed circuit
boards to prevent damage to the delicate foil. Use a soldering iron with a
tip temperature of 800 degrees or less. Use only 60/40 or 63/37 tin / lead
rosin-core solder. Do not hold the tip of a hot iron on a soldering
connection for longer than two (2) seconds.
Note: All switches on the front panel of the 104001C are used for
alignment and are covered in paragraph 3.09 through 3.014.
Terminating Impedances
3.07 Switch S1 selects the terminating impedances at the 104001C’s facility-
side ports (rcv in and xmt out). Switch S3 performs the same function for the
4001’s terminal-side ports (rcv out and xmt in). Set each switch to the 1200,
600, or 150 position as required. In general, 1200-ohm impedance is used to
interface loaded cable, 600-ohm impedance is used to interface non-loaded
cable, carrier, SFor DX signaling units, terminating sets, or station apparatus,
and 150-ohm impedance is used to provide a small amount of slope
equalization through the deliberate impedance mismatch when the module
interfaces long section of non-loaded cable (see paragraph 2.07)
Facility-Side Sealing-Current/SX-Lead Options
3.08 Switch S6 conditionsthe 104001C to supplyinternally generated 25mA
sealing current, to accept externally supplied sealing current from the distant
end of the facility, or to derive normal simplex leads on the facility side.
Select the desired facility-side sealing current/SX-lead arrangement as
follows:
For normal SX-lead derivation on the facility-side, set S6 to SX.
For internally generated 25mA sealing current on the facility
side, set S6 to SOURCE.
FIGURE 6. 104001C Option Switch and Strap Locations.

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5
To provide a return path for sealing current applied from the far
end on the facility side, set to S6 to SINK.
Note 1: For instructions on setting S6 for a bypassed signaling arrangement,
see paragraph 3.10.
Note 2: When switch S6 is set to either SX, SINK, or SOURCE, switch S8 is
nonfunctional can therefore be left in either the REV or NORM position.
Terminal-Side Sealing-Current / SX-Lead Options
3.09 Switch S7 conditionsthe 104001C to supply internally generated 25mA
sealing current, to accept externally supplied sealing current from the far end
of the facility, or to derive normal simplex leads on the terminal side. Select
the desired terminal-side or sealing-current/SX-lead arrangements as follows:
For internally generated 25mA sealing current on the facility
side, set S7 to SOURCE.
To provide a return path for sealing current applied from the far
end on the facility side, set S7 to SINK.
For normal SX-lead derivation on the terminal side set S7 to SX.
Note 1: For instructions on setting S7 for a bypassed signaling arrangement,
see paragraph 3.10.
Note 2: When S7 is set to either SX, SINK, or SOURCE, Switch S8 is
nonfunctional and can therefore be left in either the REV or NORM position.
Bypassed Signaling
3.10 For bypassed signaling i.e., to provide a straight-through SX-lead
signaling path separate from the 104001C’s transmission paths, set switches
S6, S7, and S8 as follows:
For a normal straight-through signaling path (RCV IN SX to RCV OUT SX
and XMT IN SX to XMT OUT SX), set S6 and S7 to BYP and S8 to
NORM.
For a reversed straight-through signaling path (RCV IN SX to XMT IN SX
and RCV OUT SX to XMT OUT SX), as required to compensate for
polarity reversals in DX-signaling and ground-start applications, set S6 and
S7 to BYP and S8 to REV.
Alignment
3.11 This alignment procedure is divided into three parts: gain adjustment,
output level adjustment, and equalization. The gain adjustment procedure
(paragraph 3.12) covers local prescription alignment for applications where
the circuit-layout record (CLR) transmission requirement is expressed in
terms of expected measured gain (EMG). If the CLR transmission
requirement is expressed in terms of transmission level points (TLP’s), the
output level adjustment procedure (paragraph 3.013), which covers
composite prescription alignment of the circuit in which the module is used,
should be performed instead. If equalizer settings are not given on the CLR
or if the given settings do not adequately equalize the facility, frequency
response measurements should be taken and the module’s equalizer set as
described in paragraphs 3.14 through 3.17. Because the equalizers do not
affect 1004 Hz transmission levels, equalization may be introduced after
transmission levels are set.
Gain Adjustment (for levels expressed as EMG)
3.12 If the CLR transmission requirement is expressed as EMG, proceed as
directed below. If the transmission requirement is expressed as TLP’s,
proceed instead to paragraph 3.13.
Note: When the CLR transmission requirement is expressed as EMG, both
the transmit and receive portions of the transmission measuring set (TMS)
used for alignment must be optioned for 600 ohms.
Receive Channel:
1. Determine from the CLR whether gain or loss is required in the
receive channel, and set the front-panel RCV GAIN/LOSS switch to
GAIN or LOSS as appropriate.
2. Set all front-panel RCV LEVEL DIP switches for zero gain or loss,
i.e., to the OUT position.
3. If you have not already done so, insert the module into its mounting
and apply power.
4. Determine from the CLR the amount of receive-channel gain or loss
(in dB) required. Call this amount G RCV.
5. Arrange the transmit portion of a TMS for 1004Hz tone output at a
–G RCV dBm level and for 600-ohm impedance and connect it to the
module’s RCV IN jack.
6. Arrange the receive portion of the TMS for 600-ohm terminated
measurement and connect it to the module’s RCV OUT jack.
7. Set to IN that combination of front-panel RCV LEVEL DIP switches
which adds up to the required amount of gain or loss, as verified by a
0dBm reading on the TMS.
Transmit Channel:
8. Determine from the CLR whether gain or loss is required in the
transmit channel, and set the front-panel XMT GAIN/LOSS switch
to gain or loss as appropriate.
9. Set all front panel XMT LEVEL DIP Switches for zero gain or loss,
i.e., to the out position.
10. Determine from the CLR the amount of transmit channel gain or loss
(in dB) required. Call this amount G XMT.
11. Arrange the transmit portion of the TMS for a 1004Hz output at a
–G XMT dBm level and for 600-ohm impedance, and connect it to
the modules XMT IN jack.
12. Arrange the receive portion of the TMS for 600-ohm terminated
measurement, and connect it to the module’s XMT OUT jack.
13. Set to INthat combination offront-panel XMT LEVELDIP switches
which adds up to the required amount of gain or loss, as verified by a
0dBm reading on the TMS.
Output Level Adjustment (for levels expressed as TLP’s)
3.13 If the CLR transmission requirement is expressed as TLP’s, proceed as
directed below. Please be aware that this procedure requires end-to-end
measurements.
Note: If the CLR transmission requirement is expressed as TLP’s both the
transmit and receive portions of the local transmission measuring set (TMS)
must be optioned to match the impedance of the module ports to which they
are connected. If this is not possible due to the type of TMS available, re-
option the module to match the impedance of the TMS while alignment is
performed, and be certain to re-option the module appropriately after
alignment is completed.
Receive Channel:
1. Set all front-panel RCV LEVEL DIP switches for zero gain or loss,
i.e., to the out position.
2. If you have not already done so, insert the module into its mounting
and apply power.
3. Arrange the receive portion of a TMS for terminated measurement at
the terminal-side impedance selected on the module (see note above),
and connect it to the module’s rcv out jack.
4. Request personnel at the distant (facility-side) end of the circuit to
send 1004Hz tone at the CLR-specified level. Record the level
observed on the local TMS; this level is the receive input level
because the module is now optioned for zero gain or loss and no
equalization.
5. Refer to the CLR to obtain the required receive output level.
Determine the difference between the measured receive input level
and the required receive output level.
6. Depending upon whether gain or loss is required (as determined in
the preceding step), set the module’s front-panel RCV GAIN/LOSS
switch to GAIN or LOSS as appropriate.
7. Then set to in that combination of front-panel RCV LEVEL DIP
switches which adds up to the difference determined in step 5, as
verified by a proper receive output level reading on the local TMS.

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6
Transmit Channel:
8. Set all front-panel XMT LEVEL DIP switches for zero gain or loss,
i.e., to the OUT position.
9. Arrange the transmit portion of the TMS for 1004Hz tone output at
the CLR-specified transmit input level and for the terminal side
impedance selected on the module (see note above), and connect it to
the module’s XMT IN jack.
10. Request personnel at the distant (facility-side) end of the circuit to
measure and report the level of the received 1004Hz tone.
11. Determine the difference between the actual received level at the
distant end and the desired level at that end.
12. Depending upon whether gain or loss is required to achieve the
desired level at the distant end (as determined in the preceding step),
set the module’s front-panel XMT GAIN/LOSS switch to GAIN or
LOSS as appropriate.
13. Set to IN that combination of front-panel XMT LEVEL DIP switches
which adds up to the difference determined in step 11, as verified by
a proper receive input level at the distant end of the circuit.
Equalization Adjustment
3.14 To adjust the 4001’s receive and transmit active slope equalizers when
prescription equalization settings (i.e., the amount of equalized gain at
2804Hz re 1004Hz required for each channel) are given in the CLR, simply
set the module’s front panel RCV EQL and XMT EQL DIP switches
appropriately, as directed in paragraph 3.015. If, however, prescription
equalization settings are not given in the CLR or if the given settings do not
provide adequate results, it is necessary to perform equalization adjustment
as directed in paragraphs 3.016 through 3.018.
Prescription Receive and Transmit Equalization
3.15 Equalization is introduced via the front –panel RCV EQL and XMT
EQL DIP switches. The specific amount of equalized gain at 2804Hz (re
1004Hz) introduced via each individual DIP-switch position is indicated on
the front panel adjacent to the switch. These switch positions are cumulative;
the total amount of equalized gain (0 to 7.5dB) introduced into a channel is
the sum of that channel’s DIP-switch positions set to in. Because the amounts
of required equalization given in the CLR may be specified to the nearest
0.1dB (while the RCV EQL and XMT EQL IP switches are arranged in 0.5dB
increments), use the following guidelines for rounding up or down when
setting the switches: If, for example, 0.3 to 0.7dB of equalized gain is
required, set the switches to introduce 0.5dB. If 0.8 to 1.2dB of equalized
gain is required, set the switches to introduce 1dB. Similarly, if 1.3 to 1.7dB
of equalized gain is required, set the switches to introduce 1.5dB, and so on
upward through the switches’ range. If no equalization is required for a
channel, ensure that all of that channel’s equal DIP-switch positions are set
to out.
Non-Prescription Receive-Channel Post-Equalization Adjustment.
3.16 To determine the need for receive-channel post-equalization at the local
end of the facility, and to adjust the module’s receive equalizer when
prescription settings are not given in the CLR, proceed as follows:
1. Ensure that all front-panel RCV EQL, DIP-switch positions are set to
OUT for no equalization. Then remove the module from its mounting
position, ensure that both terminating-impedance switches (S1 and
S3) are correctly set, and reinsert the module into its mounting
position.
2. Arrange the receive portion of a transmission measuring set (TMS)
for terminated measurement at the terminal-side interface impedance
selected on the module. Connect the receive portion of the TMS to
the module’s RCV OUT jack. (The transmit portion of the TMS must
remain disconnected from the module at this time.)
Note: If the TMS does not provide and impedance setting that matches the
impedance selected on the module, re-option the module as necessary for a
proper impedance match during this procedure. Then, when this procedure
is completed, reset the module’s impedance as required.
3. Have the distant facility-side end send 1004Hz test tone at the CLR-
specified level. Verify that the TMS reading equals the CLR-
specified receive level; then measure and record the level.
4. Now have the distant facility-side end send 2804Hz test tone at the
CLR-specified level. Measure and record the received 2804Hz tone
level. Subtract this 2804Hz level from the 1004Hz level measured in
step C.
5. Set to IN the proper combination of RCV EQL DIP switches that
approximates as closely as possible the measured difference, i.e., the
amount of equalized gain required, as specified in Table 4.
Non-Prescription Transmit-Channel Post-Equalization for
Intermediate Applications.
3.17 In intermediate-repeater applications, transmit-channel equalization is
often used to post-equalize the input to the module’s transmit channel in the
same manner as the module’s receive equalizer. In such applications, to
determine the need for transmit-channel post-equalization at the local end of
the facility interfacing the module’s “terminal” side, and to adjust the
module’s transmit equalizer when prescription settings are not given in the
CLR, proceed as follows:
1. Ensure that all front-panel XMT EQL DIP-switch positions are set to
OUT for no equalization. Then remove the module from its mounting
position, ensure that both terminating-impedance switches (S1 and
S3) are correctly set, and reinsert the module into its mounting
position.
2. Arrange the receive portion of a transmission measuring set (TMS)
for terminated measurement at the facility-side interface impedance
selected on the module. Connect the receive portion of the TMS to
the module’s XMT OUT jack. (The transmit portion of the TMS
must remain disconnected from the module at this time.)
Note: If the TMS does not provide and impedance setting that matches the
impedance selected on the module, re-option the modules as necessary for a
proper impedance match during this procedure. Then, when this procedure
is completed, reset the module’s impedance as required.
3. Have the distant terminal-side end send 1004Hz test tone at the CLR-
specified level. Verify that the TMS reading equals the CLR-
specified receive level; then measure and record the level.
4. Now have the distant terminal-side end send 2804Hz test tone at the
CLR-specified level. Measure and record the received 2804Hz tone
level. Subtract this 2804Hz level from the 1004Hz level measured in
step 3.
5. Set to IN the proper combination of RCV EQL DIP switches that
approximates as closely as possible the measured difference, i.e., the
amount of equalized gain required, as specified in Table 4.
Non-Prescription Transmit-Channel Pre-Equalization for Terminal or
Intermediate Applications.
3.18 In both terminal and intermediate repeater applications, transmit-
channel equalization (i.e., pre-equalization) at the local end of the facility is
normally left flat (no equalization) in favor of receive-channel post-
equalization at the distant end of the facility. In such applications, to
determine the need for transmit-channel pre-equalization, and to adjust the
module’s transmit equalizer when prescription settings are not given in the
CLR, proceed as follows:
1. Ensured that all front-panel XMT EQL DIP switches are set to OUT
for no equalization. If you have not already done so, remove the
module from its mounting position, ensure that both terminating-
impedance switches (S1 and S3) are correctly set, and reinsert the
module into its mounting position.
2. Connect the transmit portion of the TMS, arranged for the terminal-
side interface impedance selected on the module, to the module’s
XMT IN jack.

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7
Note: If the TMS does not provide an impedance setting that matches
impedance selected on the module, re-option the module as necessary for a
proper impedance match during this procedure. Then, when this procedure
is completed, reset the module’s impedance as required.
3. Send test tone at 1004Hz and 2804Hz at the CLR-specified transmit
input level toward the distant facility-side end. Have personnel at
that end measure the received levels, subtract the 2804Hz level from
1004Hz level, and report the result.
4. Set to IN the proper combination of XMT EQL DIP switches that
approximates as closely as possible the reported difference, i.e., the
amount of equalized gain required, as specified in Table 4.
TABLE 4. Equalized Gain Settings from Cable Loss Data.
1004 Hz –2804 Hz
Difference
Amount of Equalized Gain Required
0.0 to 0.2 dB
0.0 dB
0.3 to 0.7 dB
0.5 dB
0.8 to 1.2 dB
1.0 dB
1.3 to 1.7 dB
1.5 dB
1.8 to 2.2 dB
2.0 dB
2.3 to 2.7 dB
2.5 dB
2.8 to 3.2 dB
3.0 dB
3.3 to 3.7 dB
3.5 dB
3.8 to 4.2 dB
4.0 dB
4.3 to 4.7 dB
4.5 dB
4.8 to 5.2 dB
5.0 dB
5.3 to 5.7 dB
5.5 dB
5.8 to 6.2 dB
6.0 dB
6.3 to 6.7 dB
6.5 dB
6.8 to 7.2 dB
7.0 dB
7.3 to 7.7 dB
7.7 dB
4. CIRCUIT DESCRIPTION
4.01 This circuit description is intended to familiarize you with the 104001C
Prescription Line Amplifier for engineering and application purposes only.
Attempts to troubleshoot the unit internally are not recommended and may
void your warranty. Troubleshooting procedures should be limited to those
prescribed in Section 7 of this practice. Refer to the 104001C block diagram,
Figure 1. of this practice, as an aid in following this circuit description.
Note: The transmit and receive channels of the 104001C module are virtually
identical. Therefore, the description in paragraphs 4.02 and 4.03 applies to
both channels.
4.02 A transformer is used at each port (input and output) of each channel to
interface external circuits. Switch-selectable taps on the external-circuit side
of each transformer afford a choice of 1200, 600, or 150-ohm balance
terminating impedance on both sides (facility and terminal) of the module.
The internal-circuit side of each transformer is protected by a silicon voltage-
transient suppressor that limits transient voltages to a safe level and provides
surge protection. In addition, both transformers are center-tapped to derive
balanced simplex leads.
4.03 Signals entering each channel’s input port are coupled across the input
transformer and applied to the LEVEL ADJUST circuit and GAIN AMP.
The level adjust circuit is controlled by the channel’s front-panel
GAIN/LOSS and LEVEL switches. These switches allow selection of 0 to
24dB of gain or loss in 0.1dB increments. Signals at the output of the GAIN
AMP are applied to and active slope-type amplitude equalizer consisting of
the EQUALIZATION ADJUST circuit and EQL AMP. The
EQUALIZATION ADJUST circuit is controlled by the channel’s front-panel
EQL switches. These switches allow selection of 0 to 7.5dB of gain at
2804Hz (re 1004Hz) in 0.5dB increments. Signals at the output of the EQL
AMP are applied to the POWER AMP, which drives the output transformer.
4.04 The 104001C can be optioned to provide 25mA of internally generated
sealing current to metallic facilities on the facility and/or terminal sides of the
module, to accept externally generated sealing current from the far ends of
the facilities on both sides of the module, to derive normal simplex leads on
both sides of the module, or to provide bypassed (straight-through) simplex-
lead signaling via a path separate from the transmit and receive transmission
paths. Each of the 104001C’s two internal sealing-current sources has a
“ZAP” feature by which a greater amount of sealing current is provided for a
few seconds when power is initially applied to the module.
4.05 When the internal sealing-current source on the 4001’s facility side is
selected, sealing current is fed to the external 4wire facility though the
transmit output port (pins 41 and 47) and is returned to the module through
the receive input port (pins 7 and 13). When the internal sealing-current
source on the 104001C’s terminal side is selected, sealing current is fed to
the external 4wire facility through the transmit input port (pins 40 and 55)
and is returned to the module through the receive output port (pins 5 and 15).
When the externally supplied sealing current option is selected on either side
of the module, the center-tapped leads of the receive and transmit
transformers are connected together. This creates a return path that allows
the module to accept sealing current from an external source at the distant
end of the external facility. The third option settingprovides normalsimplex-
lead derivation at the module’s facility-side and/or terminal-side ports. When
optioned forbypassed (i.e., straight-through) SX-lead signaling, an additional
switch optioned selects either normal (RCV IN SX to RCV OUT SX and
XMT IN SX to XMT OUT SX) or reversed (RCV IN SX to XMT IN SX and
RCV OUT SX to XMT OUT SX) straight-through signaling.
4.06 The 400C’s facility-side (receive input and transmit output) transformers
are connected to both bridging and opening bantam-type test jacks, while the
terminal side (receive output and transmit input) transformers are connected
to opening bantam type test jacks only.
4.07 The Power Supply on the 104001C is simple series voltage regulator
that uses a zener diode as reference source. A series diode in the negative
input battery lead protects the circuit against reversed input-power
connections, and a transorb between input battery and ground limits high-
level supply transients to a safe level.
5. MECHANICAL OUTLINE
5.01 See FIGURE 2.
6. SPECIFICATIONS
Note: Transmit-channel and receive-channel specifications of the 104001C
are identical.
6.01 Electrical
Terminating impedances (all four ports):
1200, 600 or 150 ohms, balanced, switch-selectable
Flat Gain or Loss: 0 to 24dB of gain or 0 to 24dB of loss,
in switch- selectable 0.1dB increments,
with gain or loss selected via switch option
increments, prescription-set
Deviation from gain or loss setting indicated by front-panel switches:
+0.25dB maximum, re 1000Hz
Maximum Output Level: +10Bm
Total Harmonic Distortion: less than 1% at +10dBmoutput level

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8
Longitudinal Balance (each port): 55dB minimum, 150 to 3000Hz
Frequency Response (unequalized)): +0.5dB, 300 to 3000Hz, re 1000Hz
+0.3dB, 500 to 3000Hz, re 1000Hz
Amplitude Equalization:
active prescription slope-type providing from 0 to 7.5dB of gain at
2804Hz, re 1004Hz, in switch-selectable 0.5dB increments
Noise: 15dBrnC maximum at maximum gain
Delay Distortion: less than 100s, 300 to 3000Hz, re 1800Hz
(measured worst-case with equalization)
Crosstalk Loss between Channels: 85dBminimum at 1000Hz
75dB minimum at 3000Hz
Crosstalk Loss between Units in Adjacent, Above, or Below Shelf Slots:
90dBminimum at 1000Hz
85dB minimum at 3000Hz
Simplex (SX) Current:
120mA, maximum, with 5mA maximum unbalance
Internal Sealing-current Sources (facility and terminal sides):
25mA, balanced (with higher ZAP current for a few
seconds upon initial application of power to module)
Input Power Requirements when Neither Sealing-current Sources is used:
Voltage: -22 to –56VDC filtered, ground referenced
Current (at –48VDC): 75mA maximum, 30mA at idle
Input Power Requirements when Internal Sealing-current Sources are used:
Voltage: -42 to –56VDC filtered, ground referenced
Current (at –48VDC):
57mA at idle, 92mA maximum with one
sealing-current source active; 84mA at idle,
132mA maximum with both sealing-current
sources active
6.02 Environmental
Operating Environment: 20 to 130F (-7 to 54C)
Humidity: up to 95% R.H. (no condensation
6.03 Physical
Dimensions: 5.580” H x 1.420” W x 5.960” D
14.17cm H x 3.61cm W x 15.14cm D
Weight: 13 ounces (369 grams)
Mounting: relay rack or apparatus case via one position of an
Accurate Type-10 Mounting Shelf or one position of
an Accurate 246 Resistive Data Bridge Mounting Assembly
7. TESTING AND TROUBLESHOOTING
7.01 The Testing Guide Checklist (Table 5.) may be used to assist in the
installation, testing or troubleshooting of the 104001C Prescription Line
Amplifier. The checklist is intended as an aid in the localization of trouble
to a specific module. If a module is suspected of being defective, a new one
should be substituted and the test conducted again. If the substitute module
operates correctly, the original module should be considered defective and
returned to Accurate for repair or replacement as directed below. We strongly
recommend that no internal (component-level) testing or repairsbe attempted
on the module. Unauthorized testing or repairs may void the module’s
warranty. Also, if the module is part of a registered system, unauthorized
repairs will result in noncompliance with Part 68 of the FCC Rules and
Regulations.
TECHNICAL ASSISTANCE
7.02 Contact Accurate Electronics, Inc. 503.641.0118, FAX: [phone];
Mail: PO Box 1654, Beaverton OR 97075-1654.
RETURN PROCEDURE (FOR REPAIR)
7.03 To return equipment for repair, first contact Accurate Electronics, Inc.
Enclose an explanation of the malfunction, your company’s name and
address, the name of a person to contact for further information, and the
purchase order number for the transaction. Accurate Electronics willinspect,
repair, and retest the equipment so that it meets its original performance
specifications and then ship the equipment back to you. If the equipment is
in warranty, no invoice will be issued.
8. MAINTENANCE
8.01 No preventive maintenance is required. General care is recommended.
9. WARRANTY
9.01 All Accurate Electronics Inc. products carry a full FIVE (5) YEAR
warranty on materials and workmanship. See WARRANTY in front of
catalog.
Note: Warranty service does not include removal of permanent customer
markings on the front panels of Accurate Electronics’ modules, although an
attempt will be made to do so. If a module must be marked defective, we
recommend that it be done on a piece of tape or on a removable stick-on
label.
9.02 If a situation arises that is not covered in the checklist, contact Accurate
Customer Service as follows (telephone number are given below):
Contact Accurate Electronic Customer Service
9.03 If a module is diagnosed a defective, follow the replacement procedure
in paragraph 9.04 when a critical service outage exists (e.g., when a system
of a critical circuit is down and no spares are available). If the situation is not
critical, follow the repair and return procedure in paragraph 9.05.
Replacement
9.04 To obtain a replacement module, notify Accurate Electronics. Be sure
to provide all relevant information, including the 104001C part number that
indicates the issue of the module in question. Upon notification, we shall
ship a replacement module to you. If the module in question is in warranty,
the replacement will be shipped at no charge. Pack the defective module in
the replacement module’s carton, sign the packing slip included with the
replacement, and enclose it with the defective module (this is your return
authorization). Affix the preaddressed label provided with the replacement
module to the carton being returned, and ship the module prepaidto Accurate
Electronics.
Repair and Return
9.05 Return the defective module, shipment prepaid, to Accurate Electronics
Inc. :
ACCURATE ELECTRONICS INC.
ATTN: REPAIR AND RETURN
8687 SW HALL BLVD. #100
BEAVERTON, OREGON 97008 USA

ACCURATE ELECTRONICS INC Practice Section 104001C Rev B January 2014
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permission of: ACCURATE ELECTRONICS INC By accepting this document the recipient agrees to make every effort to prevent unauthorized use of this information.
9
FIGURE 1. CIRCUIT DESCRIPTION.
TABLE 5. Test Guide Checklist.
TEST
TEST PROCEDURE
NORMAL RESULTS
IF NORMAL CONDITIONS ARE NOT
MET, VERIFY:
Receive Level
Arrange transmit portion of transmission measuring set
(TMS) for 1004Hz tone output at –20dBm if module’s
RCV channel is optioned for gain or at 0dBm if
module’s RCV channel is optioned for loss. Also set
transmit portion of TMS for facility-side interface
impedance selected on module. Connect 1004Hz signal
to RCV in jack. Arrange receive portion of TMS for
terminated measurement at terminal-side inter-face
impedance selected on module, and connect it to RCV
out jack.
Signal level indicated on TMS
corresponds to receive gain or
loss setting on module.
- Power
- Wiring
- Proper impedance termination
(check for double termination)
- Impedance switches (S1 and S3) properly set
- Level switches (RCV gain/loss and RCV level)
properly set
- Replace module and re-test
Receive
Equalization
Maintain connections as above. Adjust RCV EQL
switches for no equalization (all switches set to out).
Adjust module’s receive output level for 0dBm at
1004hz. Change input frequency to 2804Hz and add
equalization (up to maximum) by setting RCV EQL
switches to in one by one.
Receive output level at 2804 Hz
increases to +7.5 dBm as
equalization is added.
- Input level at 2804Hz same as at 1004Hz
- Terminating impedance correct
Transmit Level
Arrange transmit portion of TMS for 1004Hz tone
output at –20 dBm if module’s XMT channel is optioned
for gain or at 0dBm if module’s XMT channel is
optioned for loss. Also set transmit portion of TMS for
terminal-side interface impedance selected on module.
Connect 1004Hz signal to XMT in jack. Arrange
receive portion of TMS for terminating measurement at
facility-side interface impedance selected on module,
and connected it to XMT out jack.
Signal level indicated on TMS
corresponds to transmit gain or
loss setting on module.
- Power
- Wiring
- Proper impedance terminations (check for double
terminations)
- Impedance switches (S1 and S3) properly set.
- Level switches (XMT gain/loss and XMT level)
properly set
- Replace module and re-test
Transmit
Equalization
Maintain connection as above. Adjust XMT EQL
switches for no equalization (all switches set to out.
Adjust module’s transmit output level for 0dBm at
1004Hz. Change input frequency to 2804Hz and add
equalization (up to maximum) by setting XMT EQL
switches to in one by one.
Transmit output level at 2804
Hz increases to +7.5 dBm as
equalization is added.
- Input level at 2804Hz same as at 1004Hz
- Terminating Impedance correct
FIGURE 1. CIRCUIT DESCRIPTION.

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10
FIGURE 2. MECHANICAL OUTLINE.