Black Box IC461A User manual

CUSTOMER
SUPPORT
INFORMATION
Order toll-free in the U.S.: Call 877-877-BBOX (outside U.S. call 724-746-5500)
FREE technical support 24 hours a day, 7 days a week: Call 724-746-5500 or fax [phone]
Mailing address: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com • E-mail: [email protected]
JUNE 2004
IC461A
Audio Digital Balun

1
AUDIO DIGITAL BALUN
FEDERAL COMMUNICATIONS COMMISSION
AND
INDUSTRY CANADA
RADIO FREQUENCY INTERFERENCE STATEMENTS
This equipment generates, uses, and can radiate radio-frequency energy, and if not
installed and used properly, that is, in strict accordance with the manufacturer’s
instructions, may cause interference to radio communication. It has been tested
and found to comply with the limits for a Class A computing device in accordance
with the specifications in Subpart B of Part 15 of FCC rules, which are designed to
provide reasonable protection against such interference when the equipment is
operated in a commercial environment. Operation of this equipment in a
residential area is likely to cause interference, in which case the user at his own
expense will be required to take whatever measures may be necessary to correct
the interference.
Changes or modifications not expressly approved by the party responsible
for compliance could void the user’s authority to operate the equipment.
This digital apparatus does not exceed the Class A limits for radio noise emission from
digital apparatus set out in the Radio Interference Regulation of Industry Canada.
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites
applicables aux appareils numériques de la classe A prescrites dans le Règlement sur le
brouillage radioélectrique publié par Industrie Canada.

2
AUDIO DIGITAL BALUN
TRADEMARKS USED IN THIS MANUAL
Any trademarks mentioned in this manual are acknowledged to be the property of the
trademark owners.

3
AUDIO DIGITAL BALUN
Contents
Chapter Page
1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1 Potential Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2 Calling Black Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.3 Shipping and Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4
AUDIO DIGITAL BALUN
1. Specifications
System Requirements: Dolby Digital, Dolby Pro Logic, CTS, LOGIC7, THX
Surround EX
Compatible Devices: DVDs, VCRs, camcorders, satellite receivers, home theaters,
channel processors, amplifiers, D/A converters, MPEG encoders/decoders,
switchers, and other commercial or consumer audio equipment supporting digital
audio
Transmission: Transparent to the user
Bandwidth: DC to 25 MHz
Maximum Input: 1.1 Vp-p
Insertion Loss: Less than 1 dB per balun pair over the frequency range
Return Loss: Greater than 15 dB over the frequency range
Common Mode Rejection: Greater than 60 dB @ 10 MHz
Maximum Distance (UTP): Category 5 unshielded twisted pair: 600 ft. (182.9 m)
Cable: UTP: 24 gauge or lower solid copper twisted-pair wire impedance: 100 ohms
at 1 MHz;
Maximum capacitance: 20 pF/ft.;
Attenuation: 6.6 dB/1000 ft. at 1 MHz
Pin Configuration: Tip—Signal, Ring—Ground
Impedance: Input: 75 ohms (RCA); Output: 100 ohms (screw terminals)
Connectors: (1) S/PDIF RCA male connector, (2) screw terminals
Temperature Tolerance: Operating: 32 to 131°F (0 to 55°C); Storage: -4 to 185°F
(-20 to +85°C)
Humidity: Up to 95%, noncondensing
Enclosure: Fire-retardant plastic
Size: 2.3"H x 0.6"W x 0.6"D (5.8 x 1.5 x 1.5 cm)
Weight: 1.5 oz. (42.5 g)

5
AUDIO DIGITAL BALUN
2. Overview
Connect a DVD, VCR, or satellite receiver to a digital audio home theater using
unshielded twisted-pair cable (UTP) instead of costly and bulky coaxial cable. The
Audio Digital Balun allows the digital audio signals produced by these consumer or
commerical audio devices to be transmitted via a single unshielded twisted-pair
(UTP) cable.
Used in pairs, the Audio Digital Balun connects directly to the digital audio
equipment. Connect the digital audio source up to 600 feet (182.9 m) away from a
digital audio decoder/amplifier. The balun provides built-in cable strain relief for
easy installation and reliable connectivity.

6
AUDIO DIGITAL BALUN
3. Installation
To install the Audio Digital Baluns, follow these steps:
1. Identify the balun’s pin configuration (the screw terminal’s pins are labeled
Tip and Ring). One twisted pair is required. Although the Audio Digital
Balun is not polarity sensitive, be sure to use straight-through wiring (Ring to
Ring, Tip to Tip) to eliminate potential ground-loop problems.
Figure 3-1. Straight-through polarity.
2. The Audio Digital Baluns work in pairs. Plug one balun into the digital audio
source’s digital audio output (RCA connector).
3. Plug the second balun into the digital audio decoder/amplifier’s digital audio
output (RCA connector) at the remote end.
4. Connect the two baluns together, using twisted pair cabling, as shown in
Figure 3-2.
Figure 3-2. Typical installation.
5. Power on the digital audio equipment. Make sure that all audio channels are
being received.
Audio Digital Balun
(IC461A),
top view (cover off)
Audio Digital Balun
(IC461A),
top view (cover off)
Audio Digital Balun
(IC461A)
Audio Digital Balun
(IC461A)
Digital audio source
Digital audio
decoder/amplifier
One pair of
twisted-pair cable
Twisted-pair cable,
one pair
RCA male
Tip
Tip
Ring
Ring

7
AUDIO DIGITAL BALUN
4. Troubleshooting
4.1 Potential Problems
Symptom: No audio.
Probable Causes/Solutions:
1. EMI interference. Check that the wiring is not too close to transformers or
ballasts.
2. Maximum distance (600 ft. [182.9 m]) is exceeded. Verify the cable length
between the two baluns.
3. Split pair. If the UTP pairs are split, correct the problem. Each signal pair
must be twisted.
4. Power is off. Check the digital audio equipment’s power supplies.
Symptom: Missing channels.
Probable Causes/Solutions: There is a cabling problem between the
decoder/amplifier and the audio speakers. Check the audio speaker cabling.
Symptom: Intermittent static noise on one or more channels.
Probable Causes/Solutions: Distance (600 ft. [182.9 m]) exceeded or unusual
cable attenuation. Check the cable distance and cable grade.
4.2 Calling Black Box
If you determine that your Audio Digital Balun is malfunctioning, do not attempt
to alter or repair the unit. It contains no user-serviceable parts. Contact Black Box
at 724-746-5500.
Before you do, make a record of the history of the problem. We will be able to
provide more efficient and accurate assistance if you have a complete description,
including:

8
AUDIO DIGITAL BALUN
• the nature and duration of the problem.
• when the problem occurs.
• the components involved in the problem.
• any particular application that, when used, appears to create the problem or
make it worse.
4.3 Shipping and Packaging
If you need to transport or ship your Audio Digital Balun:
• Package it carefully. We recommend that you use the original container.
• If you are shipping the balun for repair, make sure you include everything that
came in the original package. Before you ship, contact Black Box to get a
Return Authorization (RA) number.

1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax [phone]
© Copyright 2004. Black Box Corporation. All rights reserved.
Doc. No. 94-000371-A; SE-000378-A