CopperOptics PairGain PG-Flex FRC-753 User manual

PAIRGAIN TECHNOLOGIES Section 363-753-102
Technical Practice Revision 01
Engineering - PLANT Series December 18, 1996
Page 1
PG-FLEX™8 CHANNEL RT POTS UNIT
MODEL FRC-753
List # PairGain Part # CLEI Code
1 150-1353-01 VARHCGECAA
2 150-1353-02 VARHCGGCAA
CONTENTS PAGE
A. PRODUCT OVERVIEW
1. DESCRIPTION
AND FEATURES 2
2. APPLICATIONS 2
3. SPECIFICATIONS 3
4. CERTIFICATION 4
5. WARRANTY 4
B. FUNCTIONAL DESCRIPTION
6. OPERATIONAL
CAPABILITIES 6
7. FRONT PANEL 6
C. INSTALLATION AND TEST
8. UNPACKING 6
9. TURN-UP AND TESTING 6
10. TROUBLESHOOTING 6
CAUTION
This product incorporates static sensitive components.
Proper electrostatic discharge procedures must be
followed.
Figure 1. FRC-753 COT Channel Unit Front Panel. The
PairGain FRC-753 provides eight POTS interfaces between a
PG-Flex Remote Terminal and the subscriber.

Section 363-753-102
Revision 01
Page 2
A. PRODUCT OVERVIEW
1. DESCRIPTION AND FEATURES
1.01 The PG-Flex FRC-753 Channel Unit provides 8
POTS interfaces between a PG-Flex Remote
Terminal (RT) and subscribers. The FRC-753 Channel Unit
uses µ-Law PCM encoding. The unit includes status LEDs
for each line indicating idle, ringing, and off-hook
conditions, as well as an LED indicating a fault condition on
the Channel Unit. The unit provides metallic test access to
the subscriber line for connecting through an optional
metallic bypass pair.
1.02 Revision History of this practice.
Revision 02—December 18, 1996
a) Added List 2.
1.03 Features of the PG-Flex FRC-753 RT Channel
Unit:
• Eight POTS subscriber interfaces
• 64 kbps µ-Law PCM encoding
• Front panel ACTIVE LEDs indicate idle, ringing,
test access, and off-hook for each channel
• Front panel FAULT LED indicator simplifies
troubleshooting
• Pair Gain Test Controller (PGTC) Compatibility,
List 2 only
2. APPLICATIONS
2.01 Subscriber Drop Testing. For subscriber drop
testing from the central office, PG-Flex is able to
select and connect any subscriber drop to a metallic test pair
at the RT. PG-Flex extends this connection back to the COT
where it can be switched onto the test access bus, or to the
corresponding subscriber line on the COT channel card.
2.02 Test access may be achieved by placing +116V on
the subscriber’s COT tip lead for 1.5 seconds, then
removing the +116V. Depending on the configuration of the
PG-Flex system, the selected subscriber drop (assuming a
working metallic bypass pair) will be connected to either the
corresponding COT subscriber line or to the test access bus.
2.03 The test connection will be dropped when -116V is
applied to the subscriber’s COT tip for 1.5 seconds,
then removing the -116V.
2.04 Test access may also be activated through the
RS-232 Maintenance Port located on the front of the
COT Line Unit, using an ASCII terminal.

Section 363-753-102
Revision 01
Page 3
Figure 2. Typical PG-Flex Configuration.
3. SPECIFICATIONS
Analog Impedance
600 ohms
DC Loop Current
23 mA into off-hook dc resistance of 960 ohms
Ringer Output Drive
15 REN maximum per RT, 5 REN maximum
per channel
RT DC Supervisory Range
960 ohms. Maximum cable loop resistance,
minus 430 ohms for handset, is 530 ohms.
RT Idle State Loop Voltage (On-Hook)
Greater than 40 Vdc. Ring is negative with
respect to Tip
RT Loop Closure (Off-Hook) Detection
Less than 960 ohms between Tip and Ring
RT On-Hook Detection
Greater than 10 kohms
Operating Temperature & Humidity
-40° F to +150° F (-40° C to +65° C)
5% to 95% (non condensing)
Operating Elevation
-200 ft. to 13,000 ft.
(60 m to 4,000 m)
Dimensions
Height: 12.00” (30.5 cm)
Width: 1.00” (2.5 cm)
Depth: 4.50” (11.4 cm)
Weight
0.6 lb. (0.3 kg)

Section 363-753-102
Revision 01
Page 4
4. CERTIFICATION
4.01 FCC Compliance. The FRC-753 Channel Unit
complies with the limits for Class A digital devices
pursuant to Part 15 of the FCC rules. These limits are
designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial
environment. This equipment generates, uses and can radiate
radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful
interference to radio communications. Operation of this
equipment in a residential area is likely to cause harmful
interference in which case the user will be required to correct
the interference at his own expense.
4.02 Refer to the installation section of the appropriate
instruction manual for the unit you are installing to
get information on:
• Cabling
• Proper connections
• Grounding
• Line power
4.03 All wiring external to the product(s) should follow
the provisions of the current edition of the National
Electrical Code.
5. WARRANTY
5.01 PairGain Technologies warrants this product to be
free of defects and to be fully functional for a period
of 5 years from the date of original shipment, given proper
customer installation and regular maintenance. PairGain will
repair or replace any unit without cost during this period if
the unit is found to be defective for any reason other than
abuse or improper use or installation.
5.02 This module should not be field repaired. If it fails,
replace it with another unit and return the faulty unit
to PairGain for repair. Any modifications of the unit by
anyone other than an authorized PairGain representative will
void the warranty.
5.03 If a unit needs repair, call PairGain for a Return
Material Authorization (RMA) number and return
the defective unit, freight prepaid, along with a brief
description of the problem, to:
PairGain Technologies, Inc.
2120 Ritchey St.
Santa Ana, CA 92705-5101
ATTN: Customer Repair Facility
[phone]
5.04 PairGain will continue to repair faulty modules
beyond the warranty program at a nominal charge.
Contact your PairGain sales representative for details and
pricing.

Section 363-753-102
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Page 5
Figure 3. FRC-753 Block Diagram

Section 363-753-102
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B. FUNCTIONAL DESCRIPTION
6. OPERATIONAL CAPABILITIES
6.01 The FRC-753 RT Channel Unit provides 8 POTS
interfaces between the RT and subscribers, and
performs the following functions:
• 64 kbps µ-Law PCM encoding
• Applies ringing voltage
• Generates forward disconnect
• Detects an off-hook or ring-trip condition
• Connects a subscriber loop to a metallic test pair
• Protects against secondary surges
• Pair Gain Test Controller (PGTC) compatibility
6.02 A block diagram of the FLC-753 Channel Unit is
shown in Figure 3. One 8-Channel RT POTS unit
supports eight POTS interfaces.
6.03 A status LED is associated with each line to indicate
whether the line if off-hook, idle, ringing, or being
tested. A common fault LED indicates a general fault has
been detected on the card and it should be replaced.
6.04 Test access connections to a specific line circuit are
made through the maintenance terminal or by the
CO switch applying the appropriate voltage on the subscriber
line (see paragraphs 2.01 through 2.04).
7. FRONT PANEL
7.01 The front panel of the FRC-753 Channel Unit
contains the following indicators (see Figure 1):
• ACTIVE 1-8 LED Indicators
Green—the channel is off-hook.
Flashing Green—(slow flash) the channel is ringing
(the LED will track the ringing) or the line has been
switched to the test pair.
Off—the channel is on-hook.
• FAULT LED Indicator
Red—a fault has been detected by the unit.
Off—no faults are detected by the unit.
C. INSTALLATION AND TEST
8. UNPACKING
8.01 Upon receipt of the equipment, proceed as follows:
1. Unpack each container and visually inspect it for
signs of damage. If the equipment has been
damaged in transit, immediately report the extent
of damage to the transportation company and to
PairGain. Order replacement equipment if
necessary.
2. Check the contents versus the packing list to
ensure complete and accurate shipment. If the
shipment is short or irregular, contact PairGain as
described in Section 5. If you must store the
equipment for a prolonged period, store the
equipment in its original container.
9. TURN-UP AND TESTING
9.01 Table 2 provides step-by-step turn-up and test
procedures for the FRC-753 Channel Unit.
10. TROUBLESHOOTING
10.01 Table 3 provides troubleshooting procedures based
on indications displayed by the front panel
indicators of the FRC-753 Channel Unit.

Section 363-753-102
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TABLE 2. FRC-753 RT CHANNEL UNIT TURN-UP AND TESTING
CAUTION
Observe normal electrostatic discharge precautions when handling electronic equipment. Do not hold electronic plugs by
their connector edges. Do not touch components or circuitry.
Step Operation Action Observe
1 Install RT
Channel Units a. Insert each FRC-753 Channel Unit into the FRE-765 RT
Enclosure.
All LEDs on the Channel Unit will turn on for approximately
2 seconds, then scan from top to bottom, then turn off.
b. After the system has powered
up, established HDSL
synchronized communications,
and no calls are in progress,
observe the Channel Unit front
panel indicators.
ACTIVE 1 off
ACTIVE 2 off
ACTIVE 3 off
ACTIVE 4 off
ACTIVE 5 off
ACTIVE 6 off
ACTIVE 7 off
ACTIVE 8 off
FAULT off
2 Test
Subscriber
Circuits
a. Test each subscriber circuit by
placing and receiving calls. ACTIVE 1 through 8 LEDs track call as described in paragraph 7.01.
Note: To reduce the power required by the Remote Terminal, the RT Channel Unit LEDs will extinguish after a two minute time
out. Press and hold the ACO button on the RT Line unit for two seconds to reactivate the LEDs for another two minutes.

Section 363-753-102
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TABLE 3. FRC-753 RT CHANNEL UNIT TROUBLESHOOTING
Indication Problem Action
FAULT LED
on The processor in the RT Line Unit has
stopped.
Remove and replace the RT Line Unit. If the system does not restart, replace the
RT Line Unit.
Troubleshooting based on customer-originated trouble reports
No Dial tone,
Can’t Dial Short circuit, faulty COT, or faulty RT
Channel Unit.
1. Lift the subscriber pair at the RT. If dial tone is present and calls can be placed,
check for shorts toward the subscriber or on the customer's premise.
2. If you cannot hear a dial tone and/or cannot make calls at the RT with the
subscriber drop lifted, lift the jumper in the CO between the CO switch and the
COT. If you hear a dial tone and/or can make calls at the switch, replace the
COT Channel Unit and/or RT Channel Unit. Otherwise, the problem is in the
CO switch.
Phone
Doesn’t
Ring
High-resistance short
on subscriber drop,
faulty RT Channel
Unit, or faulty RT
Line Unit.
1. Check for ringing at the RT. If ringing isn’t present on the line under test, try
ringing another line terminated on the same RT Channel Unit. If ringing is
present on other lines, check for high resistance shorts on the subscriber drop.
2. If ringing isn’t present on a circuit terminated on the same RT Channel Unit, try
ringing a line terminated on another RT Channel Unit. If the line rings, replace
the RT Channel Unit. If the line doesn’t ring, replace the RT Line Unit.
Phone
Doesn’t
Stop
Ringing
Faulty subscriber
station instrument,
faulty RT Channel
Unit, or loop length
too long.
1. Phone stops ringing when using a butt-in at subscriber location:
a) Subscriber’s station instrument’s internal resistance is too high. Replace
instrument according to local policies.
2. If phone doesn’t stop ringing when using a butt-in at the subscriber location, re-
test at the RT:
a) If phone still doesn’t stop ringing, replace the RT Channel Unit.
b) Otherwise, loop length between RT and subscriber is too long.
Can’t Hear,
Can’t Be
Heard
Subscriber problem,
faulty COT Channel
Unit, or faulty RT
Channel Unit.
1. Lift the subscriber drop at the RT. If audible level is acceptable, there is a
problem toward the subscriber.
2. If audible level is too low at the RT with the subscriber drop lifted, lift the jumper
in the CO between the CO switch and the COT. If audible level is acceptable,
replace the COT Channel Unit and/or RT Channel Unit. Otherwise, the problem
is in the CO switch.
Copyright © 1996, PairGain Technologies, Inc. PairGain is a registered trademark, CopperOptics and PG-Flex are trademarks of
PairGain Technologies, Inc.