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User Guide
Issue 1, January 2008
This User Guide is applicable for serial numbers:
M93-00151 and later
with software version 1.04 and higher
Copyright © 2008 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
50038-0108, Issue 1
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Table of Contents
Introduction ..................................................................... 5
Overview ......................................................................... 8
Operation ........................................................................ 14
Technical Notes ............................................................... 20
Specifications .................................................................. 20
Appendix A—Error Code Definitions .............................. 21
Appendix B—W1 Pinout Chart ....................................... 22
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Introduction
The Model 93 is designed to test the integrity
of W1-type cable assemblies. Widely used
by the audio industry, “W1s” provide twelve
balanced signal pairs, each with an individual shield. For live production and broadcast
applications it’s critical that all signal paths
are fully functional. But without specialized
test equipment it’s impossible to confirm W1
performance. The Model 93 accomplishes
this task in a simple-to-use but technically
sophisticated manner—it’s far from just a
continuity checker. Under software control,
the internal microcontroller-based circuitry
independently tests each signal pin for
connectivity, opens, and shorts. The Model
93 can ensure that the value of a production company’s significant investment in W1
cable assemblies is maximized. When two
Model 93 units are used together they can
prove invaluable for facilities that include
permanently installed W1 cabling.
For operator convenience, testing can be
selected from among two formats: channel
mode or pin mode. Channel mode is provided specifically for field applications where
testing is most effective when oriented
toward how a W1 is actually used. Pin mode
is oriented toward supporting technical
personnel who are responsible for fabricating or repairing cable assemblies. In both
modes solid-state displays indicate which
channel or pin is being tested, along with
the test result. For ease of use the Model
93 supports both automatic and manual
testing. The unit is housed in a rugged
aluminum enclosure and is constructed for
reliable “field” performance where abuse is
often a way of life. An internal rechargeable
battery provides the operating power.
When the Model 93’s channel mode is
selected, testing is organized as twelve
signal channels. Two of the display digits
indicate which channel is currently being
tested. The display digits, depending on
which mode is selected, can also display
the test results. The results can include ALL
OK and FAIL, as well as a number of error
codes. The codes allow conditions such as
open shields or pins, crossed signal pairs,
or short circuits to be displayed. In the pin
test mode, all 39 pins associated with the
Figure 1. Model 93 Top View
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W1 connectors can be tested. Two of the display digits indicate which specific pin, or pin
group, is being tested. The other two digits
can display which pin (or pins) are connected to the pin under test.
The Model 93 is capable of testing individual
cable assemblies where both the male and
female W1 connector associated with a specific cable assembly are accessible. Referred
to as the Model 93’s local system mode,
both connectors of the designated cable
assembly are terminated on the Model 93.
This mode is appropriate for testing flexible
cable assemblies that are newly assembled
or are being prepared for temporary deployment. With rapid and complete testing, W1s
will either be confirmed as ready for use or
“flagged” for repair or replacement.
The Model 93 also allows testing of W1
“fanouts.” These cable assemblies typically
have a female or male W1 connector on one
end and twelve male or female 3-pin XLRtype connectors on the other. Connecting
this type of fanout to the Model 93 is simple.
In addition to one male and one female W1
connector, the Model 93 also provides two
3-pin XLR-type connectors, one male and
one female. Under software control, a technician can “walk through” the twelve channels,
connecting one fanout channel at a time. In
addition to testing fanouts, this feature can
find use in testing W1 cabling that terminates
on patch bays or breakout panels. As a
“bonus” the Model 93 also supports testing
of standard 3-conductor audio cables that
terminate on XLR-type connectors.
A unique testing challenge is encountered
when W1 cable assemblies have already
been “run” in preparation for a broadcast
event or have been permanently installed
as part of a facility’s infrastructure. Using
the master/slave system modes, two Model
93 units can work together to perform
end-to-end testing of in-place cabling. This
unique capability can be valuable for new
installations as well as during routine maintenance and repair. Using a separate cable
path, a bidirectional data link is established
to allow the two Model 93 units to coordinate their resources. One unit is designated
as the master while the other is designated
as the slave. Two master modes ensure
that W1 cable assemblies with either male
or female connectors on the master end
can be tested. While the buttons on the
master unit control the testing functions to
be performed, both units simultaneously
display the test status. BNC connectors are
used to establish the data link between the
two Model 93 units. This connector type
was selected because of its common use
in video applications. However, cable other
than 75 ohm coax can also be used for the
data link, including microphone, “CAT5”
data, and multi-pair “telco.”
Four pushbutton switches, five LED indicators, and a 4-digit LED display provide the
Model 93’s operator interface. The power
button is used to power up and power down
the unit. The power button is also used to
select which of the four system modes is
selected. Four LED indicators, one associated with each system mode, display which
mode is active. The up and down buttons
allow manual selection of the channel or
pins designated for testing. The up button
is also used to select which cable mode
is active. The down button is also used
to select between channel and pin mode.
The auto test button is used to enable the
two automatic test sequences. The LED
display indicates which of the twelve W1
channels or 39 connector pins is currently
being tested. And, depending on which test
is selected, will also display the test results
in a variety of ways. These green-colored
LED displays were selected for their visibility
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and long-term reliability. An LED indicator is
also provided to confirm when data associated with the master/slave mode data link is
present.
The Model 93 provides two automatic test
sequences: auto test and continuous auto
test. The auto test sequence is the unit’s
fastest test method, specifically included to
support busy field broadcast applications.
It takes less than six seconds from the time
the auto test pushbutton is pressed until
the test results are displayed. In the channel mode, auto testing begins with channel
1 and continues on through to channel 12.
When selected for pin mode auto testing will
begin with pin q and continue on through
pin g. (While available for manual testing
as a group, pins r, m, and k are not part of
the auto test sequences.) During the auto
test sequence the LED display will indicate
which channel or pin is being tested.
At the end of the entire test sequence one
of three result messages will then display:
ALL OK, FAIL, or OPEN. As expected, when
the result is ALL OK the W1 is ready for use.
A FAIL message will display if one or more
errors are detected. And OPEN will display
should no pins be detected as being connected. This typically indicates that the
cable designated for testing has not been
correctly connected to the Model 93.
The continuous auto test sequence is
enabled whenever the auto test button is
pressed and held. Using this test sequence,
the Model 93 will test all channels or pins
followed by a summary results message.
However, the difference with this test sequence is that the results for each individual
channel or pin will be displayed as testing
progresses. Whenever a defective channel
or pin is detected the sequence will pause
momentarily while the right two digits display the applicable error information. The
Press and hold auto
test button to enable
continuous auto test.
Figure 2. Model 93 Configuration—Continuous Auto Test
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System mode LED will flash
to indicate that continuous
auto test is active.
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test sequence will then continue on to the
next channel or pin. After a slight pause for
the summary results to be displayed, testing will continue, again starting with channel
1 or pin q. The continuous auto test mode
was specifically included for situations where
a more detailed view of the test results is
desired.
To ensure a thorough analysis of the connection status of a W1 cable assembly the
Model 93 is capable of testing all 39 pins
of the male and female mating connectors,
organized as 36 individual pins and one
group of three pins. This allows confirmation of correct channel wiring, as well as
detecting opens, shorts, and reverses (pair
crosses). All Model 93 input and output
circuits are extensively protected from damage due to static discharge (ESD) and DC
voltages commonly found in field-production
and broadcast environments. These voltage
sources can include tally, intercom, IFB, and
microphone phantom power among others
that might be present on a W1 cable assembly that has been designated for testing.
Contained within the Model 93’s enclosure
is a rechargeable 12 volt sealed lead-acid
battery. This will provide continuous operation in excess of eight hours before recharging is required. An external 12 volt DC power
adapter, provided with each Model 93,
allows simultaneous charging of the battery
and powering of the unit. Circuitry contained within the Model 93 implements the
actual battery charging function, minimizing recharge time while maximizing battery
life. While the power button can be used to
manually turn off the Model 93, to conserve
the battery’s energy automatic shutdown
will occur after ten minutes of inactivity.
Under software control, automatic shutdown
will also occur whenever the battery voltage
reaches its minimal acceptable value.
This prevents the battery from reaching a
deep-discharge condition. For reliability under the less-than-gentle field environments
the battery is securely clamped within the
Model 93’s enclosure. It’s expected that the
battery will provide correct operation for a
period of three to five years before replacement will become necessary. A competent
technician should be able to perform the
task in well under 30 minutes.
Overview
Power On and Off
There are two ways that the Model 93 can
be brought to its operational state, i.e., be
“powered up.” One is manual and the other
is automatic. To manually apply power to
the Model 93 tap the power on/off button. A
short “power up” sequence will commence,
first testing the LED displays and indicators, and then briefly displaying the unit’s
software version number. The unit will then
display four dashes, indicating that testing
can now begin.
The Model 93 can also be powered up by
the presence of data on the master/slave
data link. This allows unattended operation
where the Model 93 unit that is designated
as the “master” can “wake up” its companion unit. The master unit will send out data,
“waking up” the slave unit. In this case the
normal power up sequence will take place,
with the exception that at the end of the sequence the unit will be forced into the slave
mode.
No matter whether the Model 93 is manually
or automatically powered up, the voltage
of the internal rechargeable battery is automatically measured. A value of less than
10 volts will result in a low battery message
being displayed. This is followed by the
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Model 93 automatically powering down. With
a low battery condition, normal operation
can’t take place unless an external source of
nominal 12 volts DC is applied. This power
source will allow Model 93 operation as well
as charging the internal battery. Maintaining
the external 12 volt source for up to 24 hours
may be required to fully recharge the battery.
There are four ways that the Model 93 can
be “powered down.” One is manual and
three are automatic. The power on/off button can be used to manually halt the unit’s
operation; simply tap the power button.
Pressing and holding the on/off button while
the unit is operating will cause a change in
the unit’s operating mode rather than turning
off the unit.
The three automatic power down methods
are inactivity, master/slave command, and
low battery voltage. To maximize the Model
93’s battery operating time, automatic shutdown will occur after ten minutes of inactivity.
Technically, inactivity is defined as a continuous 10-minute period in which none of the
buttons are pressed. The only exception to
the inactivity timer is if the unit is operating
in the slave mode and data is present on
the master/slave data link. In this case, for
the Model 93 to automatically power down
requires that a power down command be received by way of the master/slave data link.
The final way that the Model 93 will power
down is if a low battery voltage condition is
detected. Under software control, the battery
voltage is continually monitored. A measurement of lower than 10 volts will result in an
automatic power down.
For operator convenience, upon power down
three operating conditions are saved in nonvolatile memory: operating mode, connector
mode, and channel/pin mode.
Powering the Model 93
Internal Battery
The Model 93’s enclosure includes an internal 12 volt, 1.3 amp-hour, sealed lead-acid
rechargeable battery. This type of battery
was selected for two reasons: its ability to
supply peak current and long cumulative
operating time. The LED-based displays
used in the Model 93 offer several nice
operating characteristics as well as one
limitation. The first positive is that they are
very rugged and should be able to meet the
often-harsh conditions of field production
settings. A second is that they provide a
clear indication in low-light conditions. However, as with most things one must take the
good with bad. The downside of LED displays is that they require high peak currents
for effective operation. Standard one-use
(disposable) batteries, such as the ubiquitous 1.5 volt AA style, would simply not be
suitable. The Model 93’s internal lead-acid
battery doesn’t have a problem supplying
the required peak current.
The energy capacity of the Model 93’s internal battery is such that cumulative operating
time in excess of eight hours can be expected before recharging is required. In actual
applications it can be expected that it will be
weeks, or even months, between required
charges.
External Power Source
An external source of nominal 12 volts DC
is required for Model 93 operation and battery charging. The exact voltage value isn’t
critical; anything in the range of 10 to 15
volts is acceptable. Proper battery charging
will always take place because circuitry contained within the Model 93 converts the incoming voltage to the required nominal 13.8
volt DC charge voltage. A minimum of 150
milliamperes is required for operation and
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anything additional, up to 100 milliamperes
more, will be used by the charging circuitry.
As such, a power supply with a minimum of
250 milliamperes is recommended.
A 120 volt AC input, 12 volt DC, 300 milliampere, plug-in-the-wall power supply is
included with each Model 93. While good
quality, it’s a generic unit that can be easily replaced or substituted (Studio Technologies part number 10320; Digi-Key part
number MT7146). The connector required
for the power supply source is 2.1 x 5.5 mm
with positive on the inner lead. The DC input
connector on the Model 93 is a locking
type, allowing a locking mating connector
to be attached if desired.
Stand alone, the Model 93 can function
correctly as long as the battery voltage is
10 volts or greater. It will also function correctly whenever an external power source is
connected. This flexibility is due to the presence of a secondary power supply, located
on the Model 93’s printed circuit board, that
generates the 5 volts DC required for the
logic circuitry.
The Model 93’s internal battery will charge
whenever an external power source is connected. The unit doesn’t have to be “powered up” for battery charging to take place.
The time required to fully recharge the battery will depend on its discharge state
at the time charging begins. Allowing 24
hours will ensure that full recharging will
always take place, although a shorter duration will probably be sufficient. The Model
93 implements a constant voltage charging
method. This minimizes the chance that battery overcharging will take place. Keeping
an external power source connected to the
Model 93 for long durations, or even permanently, won’t cause damage to the battery.
Note that a text message will be displayed
whenever the Model 93 is operating under
battery power and an external power source
is then connected. To indicate that the external source has been detected, the LED displays will briefly show the message CHRG.
Removing an external power source will not
result in any message being displayed.
System Modes
The Model 93 can be set to one of four
overall ways of operating. These are called
the system modes and the choices are
local, master-male active, master-female active, and slave. Refer to Figure 3 for details
The local system mode is intended for testing W1 cable assemblies where both ends
will be connected to the same Model 93.
This is the default system mode and the one
that will most commonly be used. The other
three system modes are provided so that
two Model 93 units can work together in
a master-slave arrangement. This unique
capability allows testing of cable assemblies
that are permanently installed or already
deployed in a facility or venue. Specifically
this is the situation where the connectors
on both ends of a single W1 cable assembly are not accessible for connection to the
same Model 93.
To select the desired system mode, press
and hold the power button. The four
modes will “cycle” through. Release the
power button when the appropriate indicator light is active. The selected system
mode will generally remain in effect until
it is manually changed. Power cycling the
Model 93 will not cause it to change or revert to a “default” setting. The exception
is in the master-slave situation where a
Model 93 configured for master-male active
or master-female active can “force” its companion unit into the slave mode.
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Figure 3. Model 93 Configuration—System Modes
Press and hold power
button to cycle through
system modes.
Cable Modes
The Model 93 offers four cable modes. Refer
to Figure 4 for more details. The W1 to W1
cable mode allows testing of W1 assemblies that have a male W1 connector on
one end and a female W1 connector on the
other end. These are typically referred to as
“standard” W1 cables. Refer to Appendix B
for W1 wiring details. In the W1-M to XLR-F
cable mode the Model 93 is ready to test W1
cable assemblies that have a male W1 on
one end and twelve 3-pin female connectors
on the other. This type of cable assembly
is typically referred to as a W1 “fanout.” In
the W1-F to XLR-M cable mode the Model
93 is configured to test W1 fanout assemblies that have a female W1 on one end and
twelve 3-pin male connectors on the other.
The XLR to XLR cable mode allows testing
of standard audio cables that have a 3-pin
male XLR connector on one end and a 3-pin
female XLR connector on the other end.
To select the desired cable mode is simple.
Press and hold the button to the left of the
up arrow; the Model 93 will slowly “cycle”
among the four choices. To select the
desired cable mode, release the up button when the appropriate indicator light
is active. The decimal point portion of the
displays is used to indicate the active cable
mode. The selected cable mode will remain
in effect until it is manually changed. Powering cycling the Model 93 will not cause it to
change or revert to a “default” setting.
Channel/Pin Mode
The Model 93 offers two basic ways of
testing cable assemblies: channel mode
or pin mode. Refer to Figure 5 for details.
The channel mode is available for use in all
four of the cable modes: W1 to W1, W1-M
to XLR-F, W1-F to XLR-M, and XLR to XLR.
Channel mode is generally appropriate for
rapid field testing of existing inventory of
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Press and hold
“up” button to
cycle through
cable modes.
Fanout:
W1 female
to XLR male
Fanout:
W1 male to
XLR female
W1 to W1
XLR to XLR
Figure 4. Model 93 Configuration—Cable Modes
W1 and XLR cables. Pin mode is only available in the W1 to W1 and XLR to XLR cable
modes. It is not offered with the other two
cable modes as it’s not appropriate for use
with W1 “fanouts.”
In the channel mode W1 testing is organized as twelve 3-conductor groups. The
3-conductors consist of a shield and a signal pair. In standard W1 cable assemblies
these twelve channels are wired using 36
pins of 39 provided on W1 connectors;
pins r, m, and k are generally not used.
The pin mode is provided so that a detailed
view of the signal paths associated with a
cable assembly can be obtained. In the pin
mode testing can be performed on all 39
pins of a W1 connector associated with a
W1 assembly, although pins r, m, and k are
tested as a group. Pin mode is useful when
fabricating new W1 assemblies or repairing
cable assemblies which the channel mode
has identified as being defective.
The button located to the left of the down
arrow is used to select between channel
mode and pin mode. Pressing and holding
this button for two seconds will cause the
mode to change between channel mode
and pin mode, or vice-versa. As previously
discussed, only when the cable mode is
selected for W1 to W1 or XLR to XLR is it
possible to select pin mode. The indicator
light associated with the active cable mode
is used to display whether channel mode or
pin mode is selected. When channel mode
is selected the light is lit steadily. The light
will flash to indicate that pin mode is selected. The selected mode, channel or pin, will
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Press and hold “down” button to select
between channel and pin mode. Pin
mode is only available in the W1 to W1
and XLR to XLR cable modes.
Figure 5. Model 93 Configuration—Channel/Pin Mode
The active cable mode
LED will flash when pin
mode is active.
remain in effect until it is manually changed.
Powering down the Model 93 will not cause
this mode to change or revert to a “default”
setting.
Operation
It’s now time to actually test cable assemblies using the Model 93.
Local Mode Operation
The following four sections provide details
on using the Model 93 when the system
mode is selected for local.
System Mode:
Local Cable Mode: W1 to W1
When the cable mode is selected to W1 to
W1 the Model 93 is ready to test W1 cable
assemblies where both ends are terminated
to W1 connectors. In this case the cablemounted W1 connectors should be mated
with those on the Model 93. Ensure that the
connectors are “locked” together using the
outer rings to ensure that a reliable interconnection has been made. Automatic or
manual testing can now begin.
Tapping the auto test button will initiate
a rapid scan of all the channels or pins,
depending on whether channel or pin mode
is selected. At the end of the test sequence
one of three messages will display: ALL
OK, FAIL, or OPEN. ALL OK indicates that
the cable assembly is ready to be placed
into service. FAIL indicates that one or more
failures were detected during the test sequence. If FAIL displays then manual testing of the channels or pins should be used
to identify where the specific problem or
problems are located. OPEN indicates that
no connections were detected, most likely
the result of one or both of the W1 connectors not being correctly terminated on the
Model 93.
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Pressing and holding the auto test button
for two seconds will initiate a continuous
auto test mode. The local mode LED will
flash when continuous auto test mode is
active. In this mode each channel or pin will
be sequentially tested and the result displayed in real time. The left two digits of the
display will indicate the channel or pin being
tested while the right two digits will indicate
the result. In the channel mode the result
will be either OK or one or more of the nine
possible error codes. The label on the front
of the Model 93 contains a brief summary
of the error codes. A detailed description of
the error codes can be found in Appendix
A. In the pin mode the displayed result will
be the numeric code for the pin or pins that
are connected. A one-to-one relationship
between the pin being tested and the connected pin is the desired result. If no pin
is detected as being connected to the pin
selected for testing two dashes (- -) will display. At the end of each full test sequence a
summary result will display: ALL OK, FAIL,
or OPEN. The meaning of the three possible
results is the same as with the auto test
function, discussed in the previous paragraph. After a slight pause to display the
summary result, the continuous auto test
mode will begin another complete test of all
the channels or pins. To cancel continuous
auto test simply press and release the auto
test, the channel up, or the channel down
select buttons.
At any time manual testing of individual
channels or pins is possible. The buttons
adjacent to the up and down arrows are
used to select the channel or pin to be
tested. The left two digits of the display will
indicate which channel or pin is currently
being tested. The right two digits will display
the results of the test. In the channel mode
the results will be either OK or one or more
of the nine possible error codes.
In the pin mode the light indicating that W1
to W1 mode is active will flash. The test
results displayed will be the pin or pins
that are connected to the pin selected for
testing. If no pin is detected as being connected two dashes (- -) will display. Repeat
testing of the selected channel or pin will
take place every two seconds. The displayed results will refresh with each test
cycle.
System Mode:
Local Cable Mode: W1-M to XLR-F
When the cable mode is selected for
W1-M to XLR-F the Model 93 is configured
to test W1 “fanouts” that have an W1 male
on one end and twelve 3-pin female XLR
connectors on the other.
Begin testing by connecting the fanout’s W1
male connector to the female W1 connector
located on the right side of the Model 93.
Ensure that a solid connection is made by
“locking” the connectors together using the
outer ring. Each fanout channel can now
be individually tested. Start by plugging the
fanout’s female XLR connector associated
with channel 1 into the male XLR connector
located on the left side of the Model 93. Use
the buttons adjacent to the up and down arrows to select channel 1 for testing. The left
two display digits will indicate the selected
channel. The right two display digits will
indicate the test result. The result will either
display an OK or one or more of the nine
error codes. OK indicates that the connections associated with channel 1 are correct.
If the E1 error code is displayed, be certain
to use the channel select buttons to manually “step through” all channels looking
for an OK result. This will identify whether
the fanout’s XLR connector has been labeled with the incorrect channel number.
After channel 1 has been tested remove
its associated female XLR connector from
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the Model 93 and in its place connect the
connector associated with channel 2. Use
the manual channel select buttons to select
channel 2 for testing. Repeat this process for
all twelve of the fanout’s channels.
Note that in the W1-M to XLR-F cable mode
only channel mode is available. In addition,
the auto test and continuous auto test sequences are not available. Also, the Model
93 doesn’t directly support fanouts that
contain a mixture of female and male XLR
connectors. In this case the use of gender
changers or “turn arounds” is recommended.
System Mode:
Local Cable Mode: W1-F to XLR-M
When the cable mode is selected for W1-F
to XLR-M the Model 93 is configured to test
W1 “fanouts” that have an W1 female on one
end and twelve 3-pin male XLR connectors
on the other.
Begin testing by connecting the fanout’s W1
female connector to the male W1 connector located on the left side of the Model 93.
Ensure that the connection is made solidly
by “locking” the connectors together using
the outer ring. Each fanout channel can now
be individually tested. Start by plugging the
fanout’s male XLR connector associated
with channel 1 into the female XLR connector located on the right side of the Model 93.
Use the buttons adjacent to the up and down
arrows to select channel 1 for testing. The
left two display digits will indicate the selected channel. The right two display digits will
indicate the test result. The result will either
display an OK or one or more of the nine
error codes. OK indicates that the connections associated with channel 1 are correct.
If the E1 error code is displayed, be certain
to use the channel select buttons to manually
“step through” all channels looking for an
OK result. This will identify that the fanout’s
XLR connector has been labeled with the
incorrect channel number. After channel 1
has been tested remove its associated male
XLR connector from the Model 93 and in its
place connect the connector associated with
channel 2. Use the manual channel select
buttons to select channel 2 for testing. Repeat this process for all twelve of the fanout’s
channels.
Note that in the W1-F to XLR-M cable mode
only channel mode is available. In addition,
the auto test and continuous auto test sequences are not available. Also, the Model
93 doesn’t directly support fanouts that
contain a mixture of male and female XLR
connectors. In this case the use of gender
changers or “turn arounds” is recommended.
System Mode:
Local Cable Mode: XLR to XLR
In the XLR to XLR cable mode the Model 93
allows testing of standard audio cables that
use a 3-pin male XLR connector on one end
and a 3-pin female XLR connector on the
other. Begin by plugging the cable’s female
connector into the Model 93’s male connector, located on the left side of the unit. The
cable’s male connector should mate with the
female connector located on the right side
of the Model 93. Testing can take place in
either the channel mode or the pin mode. In
the channel mode the left two display digits
will always show XL, indicating that the XLR
to XLR cable mode is active. The right two
digits will either show OK or one or more of
the nine error codes.
In the pin mode the light indicating that XLR
to XLR mode is active will also flash. In this
mode the left two digits will display the pin
selected for testing. The exact text will be X1,
X2, or X3, indicating XLR connector pins 1,
2, or 3. The up and down buttons are used
to select the desired pin. The right two digits
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will show the pin or pins that are connected
to the pin selected for testing. Repeat testing of the cable, when in channel mode, or
the specific pin, when in the pin mode, will
take place. The displayed results will refresh
with each test cycle.
Master/Slave Mode Operation
A challenge is encountered when testing
cable assemblies where both ends can’t
be physically connected to one Model 93.
This occurs in cases such as where W1s
are permanently installed in stadiums and
arenas, or when portable cabling has been
“run” and can’t be accessed easily. Using
two Model 93 units, virtually any W1 cable
assembly, fan out, or even 3-pin XLR cables
can be tested.
The master/slave mode is created in the
Model 93’s hardware and software so that
the unit’s functions are “split” into a sendtest-signals portion and a receive-testsignals portion. A communications link is
established between two Model 93 units,
allowing the two functions, send and receive, to work together. The data passing
in each direction on the data link effectively
“couples” the two Model 93 units into one.
One unit is designated as “master” and
coordinates the activities of a test. The
“slave” unit follows the commands of the
master, performing the actions requested
and returning test results as required.
Master/slave testing operation is quite easy
to initiate and use. But the flexibility provided by the Model 93’s multiple operating
modes can be a bit tricky to get one’s head
around. While this user guide will document
the basic “hows and whys” of master/slave
operation, only experience can serve as the
best teacher. It’s recommended that some
“bench” experimentation be done prior to
going full bore out in the field.
Master/Slave Data Link
For two Model 93 units to be used in a
master/slave arrangement they must be
interconnected with a 2-conductor signal
path. This connection is referred to as the
master/slave data link. It supports the transmission of bi-directional serial data as well
as linking the power supply common connections of both units. A BNC connector
is used for the master/slave data link. This
type of connector was selected not because
of a specific technical requirement, but because of its wide popularity in the broadcast
and video industry. In many applications
where W1 cable assemblies are to be tested
there will also be BNC-terminated video cables present. This will most likely allow the
easier method of interconnecting two Model
93 units. However, there’s no reason that
other types of cable can’t be used. Options
can include shielded microphone cable and
twisted pair telephone cable. While using
coax will allow the greatest distance between Model 93 units, even twisted pair has
been tested at over 4000 feet! This should
be well in excess of the length of any W1
cable assembly that needs to be tested.
It’s important to note that two metallic connections must be made between the master
and slave Model 93 units. When using a
coaxial cable the two metallic connections
would consist of the inner conductor and
the shield. Alternately pins 2 and 3 of a
standard audio cable that uses XLR connectors would serve the purpose. However, any
transformers, “baluns,” or capacitors in the
connection path that provide DC isolation
will prevent master/slave operation.
After interconnecting two Model 93 units, it’s
quite easy to confirm that the master/slave
data link has been established. Temporarily
designate one of the units as slave. Be sure
that it is powered down. Turn on the other
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(master) unit by tapping its power button.
Then press and hold its power button until
the system mode has changed to mastermale active or master-female active. At this
point if the connection is valid data coming from the master Model 93 will “wake
up” the slave unit. The active LED, located
below the BNC connector, on each unit will
flash as data packets move between the
units. Once data link operation has been
confirmed power down the unit designed
as master. The slave unit should also power
down in response to a command from the
master unit.
Note that maintaining a short circuit on
the Model 93’s data link BNC connector
is something to avoid. Due to an idiosyncrasy in the operation of the data communications transceiver integrated circuit an error
in the data link wiring can force the Model
93 to stay in the powered up state. The
10-minute inactivity timer will not be able to
power down the unit; nor will a low-batteryvoltage condition be able to invoke a power
down either. Damage to the battery will
occur if a deep discharge state is reached.
This situation is not something that the
Model 93’s designers are especially proud
of, but they weren’t aware of the condition
until it was too late to make a change. And
contacting the world-class maker of the integrated circuit didn’t get much of a response
except “hmmm…” So in conclusion, as long
as the BNC connector isn’t presented with a
short circuit or a low impedance load condition things will work fine.
Master/Slave Cable Testing
Once the data link has been established
between the two Model 93 units testing
operation can begin. Start from the condition of having both units in their powered
down state. Then review the desired testing
scenario, knowing exactly which cable
assembly is going to be tested first. Designate one of the Model 93s as the master
unit. There’s no requirement as to which
unit is the master and which unit is the
slave. Typically the Model 93 that’s most
conveniently accessible should be the
master unit. For example, when testing W1s
in a stadium, it probably makes sense to
have the master situated in the truck dock
or main wiring location. Then the slave unit
can move among the destination locations
such as the broadcast booth, side of the
field, etc.
Now activate power to the unit that has
been designated as master. Ignore the status of the data link active LED and whether
or not the slave unit powers up. Before
these issues come into play a couple of
other things must first be accounted for.
On the master unit, set the cable mode to
match the type of cable to be tested. If, for
example, the cable to be tested has W1
connectors on each end select the cable
mode as W1 to W1. Another example would
be if the cable to be tested has an W1
female on one end that “breaks out” into
twelve XLR males on the other end. This
would necessitate setting the master unit’s
cable mode to W1-F to XLR-M.
The final step is to set the master unit’s
system mode. This is a little tricky to understand but we’ll work through it! Begin by
confirming the exact type of connector that
is to be connected to the master unit. For
example, while the cable mode might be
set for W1 to W1, there’s no requirement as
to which connector end, male or female, is
physically located near the Model 93 that’s
been designated as master. For our example let’s specify that an W1 male connector
is on the end of the cable that’s to be attached to the master Model 93 unit. To meet
the needs of this situation, set the master
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unit’s system mode for Master-Female
Active. This is accomplished by pressing
and holding the power on/off button until
the desired system mode is enabled.
At this point the master unit is configured
to perform the required cable test. To review, the cable mode has been set to match
the type of cable to be tested and the system mode has been selected to activate
the connector type required for the test
environment.
Once configured to the desired system
mode, the master Model 93 should have
caused the slave Model 93 to power up.
The master/slave data active LEDs on both
units should indicate that data is passing
back and forth. The slave Model 93 should
have its system mode LED indicating that
slave mode is active. The auto test and
manual channel select (up and down) buttons on the master unit perform the same
functions as if the local system mode was
selected. On the slave unit the auto test and
manual channel select buttons are disabled.
The power on/off button on the slave unit
remains active but isn’t generally utilized
during master/slave operation.
Connect the cable to be tested to the master and slave Model 93 units. In the example
covered a few paragraphs previously, an
W1 male would be connected to the master
Model 93. An W1 female would be connected to the slave Model 93. Testing functions
can only be controlled by the master Model
93. However, the test results will display on
both the master and slave Model 93 units.
This ensures that someone assisting at the
slave position is kept “in the loop” about the
testing process. To the user, the master unit
should “look and feel” just as if it was set for
local system mode. The auto test, continuous auto test, and manual channel or pin
tests can be used as desired.
After testing has been completed powering down the master Model 93 will also
cause the slave Model 93 to power down.
An inactivity timer shutdown of the master
Model 93 will also cause the slave unit to
power down. Manually powering down the
slave Model 93 will cause the unit to shut
down and end any tests in progress. But the
unit will immediately power on again in response to the master unit data commands.
Only by disconnecting the data link connection can the slave unit be independently
turned off. (But this isn’t something that one
would typically want to do anyway!)
“Jumper” Cables
In many cases it will probably be necessary to use W1 or 3-pin XLR “jumper” cable
assemblies to connect the master and
slave Model 93 units to the cables to be
tested. For example, a flexible W1 cable
assembly might be required to connect a
panel-mounted (bulkhead) W1 connector to
a Model 93. In this case be certain that the
cables that are going to be part of the test
setup are themselves tested first using the
Model 93’s local system mode. Don’t add
variables to an already fairly complicated
situation!
Ten Steps to Success
With some practice master/slave mode
operation should become second nature.
The key is to follow a logical setup and
configuration sequence before attempting
to test a cable assembly. This will make testing a simple matter, rather than leading to
a confusing situation! The steps might be
organized as follows:
1. Deploy two Model 93 units at the ends
of the cable or cables to be tested.
2. Establish the data link connection and
confirm that it’s functioning correctly.
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3. Turn off both units.
4. Designate one unit as master and power
up that unit.
5. On the master unit, select the cable
mode as required for the cable under
test.
6. Identify the type (sex) of the connector
to be connected to the master unit.
7. On the master unit, select the system
mode (master-male active or masterfemale active) so as to activate the
connector that will mate with the cable
to be tested.
8. Confirm that the slave unit has automatically powered up and its system mode
is set for slave.
9. Connect the ends of the cable to be
tested to both the master and slave
units.
10. Use the buttons on the master Model 93
to perform the desired tests. The displays on both the master and the slave
units will display the test results.
Technical Notes
Theory of Operation
At its core the Model 93 uses a fairly simple
method to test the signal paths of the connected cables. Under software control a
test signal can be assigned to any one of
the first 36 pins of the male W1 connector,
pins r, m, and k as a group, and the three
pins of the male XLR connector. This test
signal is a DC level of approximately 4 volts
which is created by way of a pulse-widthmodulator output on the microcontroller.
Again under software control, the DC level
of signals present on the first 36 pins of the
female W1 connector, pins r, m, and k as a
group, and the three pins of the female XLR
connector can be measured. An analog-todigital converter input on the microcontroller
measures the actual voltages. All signals
are generated and measured in reference
to the power supply, battery, and data link
common connection.
Resistors, in series with each of the male
and female connector pins, along with
other protection circuitry limit the current
that can come into or go out of the Model
93. This will prevent most external DC or
static-discharge signals from damaging
the Model 93.
The Model 93’s channel and pin test routines specify which male (output) pin is active and then scans the female (input) pins,
measuring the voltage present on each pin.
The data is analyzed and interpreted so as
to provide meaningful results to the user.
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Specifications
Application: electrical testing of standard W1 cable
assemblies
Connectors:
W1 Cable Assemblies: one male and one female
39-pin circular W1-type
Fanout and XLR: one male and one female 3-pin
XLR-type
Data Link: BNC
12 Volt DC Power In: coaxial power jack, 2.1 x 5.5
mm, locking bushing, compatible with Switchcraft
S760K plug
Power Source:
Internal: 12 volt 1.3 amp-hour sealed lead-acid
battery. Operating time 8 hours minimum with fully
charged battery. Recharge time 8 hours maximum.
External: 12 volts DC nominal, acceptable range
10-15 volts DC; 250 mA minimum recommended
for operation and battery charging. Units shipped
to North America and Japan include a 120 V input/
12 Vdc output power supply.
Master/Slave Operation:
Data Link: modified LIN bus, 1200 bit/s
Maximum Distance between Units: tested to 2400
feet using Belden 1694A coaxial cable and 4000 feet
using standard CAT5E UTP
Dimensions:
Height: 5.0 inches (12.7 cm)
Width: 5.0 inches (12.7 cm)
Length: 11.0 inches (27.9 cm)
Overall Length: 12.5 inches (31.8 cm)
Weight: 5.5 pounds (2.5 kg)
Specifications and information contained in this User
Guide subject to change without notice.
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Appendix A
Error Code Definitions
In this section a detailed description will
be given of the Model 93’s nine error codes.
The error codes are only displayed when
the Model 93 is selected for the channel
mode and an issue is detected. In the
channel mode the three conductors associated with a W1 channel are tested for
shorts, opens, and proper connectivity. All
the tests are made in relation to the pins
associated with the specific channel on
the W1 connectors.
E1: Open Shield and Pair
No connections have been detected on
the shield, signal low, and signal high
paths of the channel selected for testing.
The channel is completely “open.”
E2: Open Shield
No connection has been detected on
the shield path of the channel selected
for testing.
E3: Open Pair
No connection has been detected on the
signal low path, the signal high path, or
both the signal low and signal high paths.
E4: Reversed Pair
The signal path has been reversed or
“flipped.” The signal low connection on the
female connector end of the cable under
test is connected to the signal high connection on the male connector end of the cable
under test. And, as expected, the signal
high connection on the female connector
end of the cable under test is connected to
the signal low connection on the other end.
E5: Shorted Shield to Pair
A connection has been detected between
the shield path and the signal low path,
between the shield path and the signal high
path, or between the shield path and both
the signal low and signal high paths.
E6: Shorted Pair
A connection has been detected between
the signal low path and the signal high path.
E7: Incorrect Shield Connection
The shield pin on the female connector end
of the cable under test is connected to the
pin designated for signal low or signal high
on the male connector end of the cable
under test.
E8: Incorrect Pair Connection
The signal low pin or the signal high pin
on the female connector end of the cable
under test is connected to the pin designated for shield on the male connector end
of the cable under test.
E9: Channel-to-Channel Error
This is a somewhat general-purpose error
code. It indicates that one or more problems exist between the pins associated with
the selected channel on the female connector end of the cable under test and pins
associated with other channels on the male
end of the cable.
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Appendix B
W1 Pinout Chart
Model 93 W1 W1 W1
Pin Test Order Pin Number Channel Function
1 q SHIELD
5 p 1 +
6 n –
2 X SHIELD
3 W 2 +
7 A –
4 P SHIELD
8 N 3 +
9 f –
10 M SHIELD
16 L 4 +
17 e –
11 K SHIELD
12 J 5 +
18 d –
13 H SHIELD
19 G 6 +
20 c –
14 F SHIELD
15 E 7 +
21 b –
23 Z SHIELD
24 D 8 +
29 a –
25 Y SHIELD
30 C 9 +
31 B –
26 V SHIELD
27 U 10 +
32 j –
22 T SHIELD
28 i 11 +
33 h –
34 S SHIELD
35 R 12 +
36 g –
37* r, m, k --- ---
* Connected to allow testing of spare W1 pins.
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