JK Audio Four IFB User Manual

Four IFB

Multi Line Phone Bridge

User Guide

JK Audio

Important Safety Instructions

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not expose this unit directly to water. Although this unit is
designed to be as moisture repellent as possible, it is not in­tended to be used unprotected in the rain, under water, etc. This
unit is neither 100% water proof nor water tight. When used in a
wet or damp environment, battery power is recommended.

6. Do not place liquid filled containers on the unit such as water
glasses, coffee cups, etc.

7. Clean only with dry cloth.

8. Install in accordance with manufacturer's instructions.

9. Do not install near heat sources such as radiators, heat regis­ters, stoves or other devices that produce excessive heat.

10. Do not defeat the safety purpose of the grounding-type plug.
The grounding prong is provided for your safety. If the provided
plug does not fit in your outlet, consult an electrician for replace­ment of the obsolete outlet.

11. Use only the 3 prong grounded AC cable provided with the unit
when connecting to AC power.

12. Use of a surge suppressor for AC power and phone lines is rec­ommended.

13. Unplug this unit during lightning storms or when unused for long
periods of time.

14. Protect the power cord from damage at all times. Special atten­tion should be paid to the location where the cable connects to
the unit and to the AC outlet.

15. Refer all servicing to qualified personnel.

2

Introduction

Four IFB is a four position analog telephone line interface de­signed specifically to provide flexible listen only IFB* for television
field production use. In addition to the four line- level balanced
XLR outputs, the unit is equipped with one balanced XLR line level
monitor input and one balanced XLR monitor output. Each IFB
output, and the monitor input / output jacks, may be separately
connected to one of the four analog phone lines through the use of
rotary line selector switches. A telephone handset may also be
connected for use with the monitor line selector switch. Level of
each of the six XLR jacks is adjustable individually with independ­ent volume controls.

Individual on-hook/off-hook function for each phone line is con­trolled by the Monitor Add and Drop switches. The phone line to
be controlled with these switches is determined by the Monitor ro­tary line selector switch. On-hook / off-hook relay condition will be
maintained regardless of whether an active POTS line is physically
connected to the unit, or if the unit is in a powered "on" state or
not. Temporary power loss will not disconnect an active phone
line.

The position of the monitor rotary line selector switch determines
which line is added or dropped. Calls may be placed directly from
the unit with the integrated DTMF keypad. No external dialer is
needed.

Four IFB is designed to be used in a variety of environments and
weather conditions. Although the unit is not "waterproof", all con­trols and components are dust and moisture resistant. A non­removable hinged cover protects the unit's selector switches, add/
drop buttons and keypad while the enclosure design protects the
volume controls from physical damage. When used in a wet or
damp environment, battery power is recommended.

*IFB is a broadcast industry acronym which stands for Interruptible
Fold Back. The IFB signal is typically a Program Line (PL) signal
from the studio console.

3

Quick Setup Guide

1. Connect AC power to the
unit with the provided AC
cable. The AC power
LED should light green.

2. Connect up to four ana­log (POTS) telephone
lines to the RJ-11 jacks.

3. Connect a handset to the
monitor handset jack and/or
connect the Monitor Send and
Receive XLR jacks to your
audio equipment for commu­nication.

4. Connect the IFB XLR
output(s) to your audio
equipment for distribution
of IFB audio feeds.

NOTE: You cannot connect a

mic directly to the Monitor
Send SLR. This is a line level
input.

4

Quick Setup Guide

5. Turn on the Power switch.
The power LED should
light red.

6. Rotate the Monitor selector
switch to the desired Line
position. Line 1 = phone
line connected to RJ-11
marked Line 1.

7. Press the Add button.
This will take the selected
line off-hook. The
corresponding Line LED
will light green.

8. Dial the call with the DTMF keypad.

You may now communicate with the called party on Line

1 through the Monitor handset or equipment connected to
the Monitor Send and Receive SLR jacks (optional).

Repeat steps 6-8 for Lines 2-4.

5

Quick Setup Guide (continued)

9. Use the IFB 1-4 rotary
switches to select which
phone line audio will be
sent to the corresponding
IFB XLR output jack.

Example: Setting IFB 1
rotary switch to “Line 4”
will send audio from
phone line 4 to the IFB
XLR output 1.

10. Adjust audio levels as needed using corresponding volume
controls.

6

Quick Setup Guide (continued)

11. To drop a call, rotate the Monitor selector switch to the

desired Line position. Line 1 = phone line connected to

the RJ-11 marked Line 1.
Press the Drop button.
This will drop (hang up)
the call on the selected
line. The corresponding
Line LED will go dark.

12. After use, be sure to turn off the power switch.
The battery will lose charge if the power switch is left

on and there is no AC power source present, even if
the unit is not in use.

7

Features

1 2 3 4 5 6 7

8

Operation (continued) Features

1. IFB Receive volume controls - Controls the level of audio present
on the corresponding IFB XLR output jacks.

2. Monitor Receive volume control - Controls the level of audio pre­sent on the Monitor Receive XLR output jack.

3. Monitor Send volume control - Controls the level of audio sent
into the phone line from the Monitor Send XLR input.

4. Line LED indicators - These bi-color LED indicators will inform
you of line state at a glance.

Unlit - When the relay that controls the line is in the on-hook

state, the LED will remain unlit.

Green = OK - A green LED means the relay that controls the line

is off-hook and an active phone line is physically connected.

Red = Warning - If the LED lights red this means that there is a

problem with the line. The red LED indicates that the relay that
controls the line is in its off-hook state but there is no active
phone line present.

These LED's also function as visual ring indicators. The LED will

flicker green when ring voltage is present on the corresponding
phone line.

5. Green LED AC indicator - This LED will light green whenever the
unit is connected to an active AC power source, regardless of on/
off power switch position.

6. Red LED power indicator - This LED will light red when unit
power is in the "On" position. If the unit is operating on battery
power, this LED will also indicate the condition of the battery.
The LED will only light red on battery power when voltage level is
>+7 VDC.

7. Power on / off switch

9

Features (continued)

11 8 9 10

10

13 12

Operation (continued) Features (continued)

8. AC power jack - 100-240 VAC power jack

9. Monitor Send XLR input - Line level input for sending audio

down the phone line designated as Monitor. This is a line level
input and will NOT accept a microphone directly. To use this
input to send audio you must provide a line level signal from a
device such as a mixer or mic pre-amp.

10. Monitor Receive XLR output - Line level output containing audio

from the phone line designated as Monitor.

11. IFB 1-4 XLR outputs - Line level outputs containing audio from

the phone line corresponding to each IFB 1-4 selector switch
position.

12. Monitor handset jack - RJ-22 handset jack biased for handsets

with electret type microphones. This jack allows communication
to the phone line designated as Monitor.

13. Phone line jacks 1-4 - RJ-11 telephone line jacks for connection

to analog (POTS) telephone lines.

11

Features (continued)

14

15

18 19

17 16 20

12

Operation (continued) Features (continued)

14. IFB 1-4 selector switches - These rotary switches control from

which phone line audio passes to the corresponding IFB XLR
output jack. For instance, IFB 1 rotary switch set to position 4
would send audio from phone line 4 to the IFB 1 output.

15. DTMF keypad - Used to dial calls on the Monitor phone line.

16. Monitor selector switch - This rotary switch determines which

phone line is designated as Monitor. For instance, setting this
switch to position 4 would allow phone line 4 to take advantage
of all Monitor functions.

17. Add button - Pressing this button takes the Monitor phone line

off-hook.

18. Drop button - Pressing this button drops (hangs up) any call on

the Monitor phone line.

19. Control cover - Hinged control cover protects rotary switches,

buttons and keypad. Cover locks into place with ½ turn of lock­ing latch.

20. Battery - Slide out compartment for a single 9 VDC battery.

All active functions of the Four IFB require that AC or battery
power is present and that the Power Switch is in the “On”

position.

13

Operation

Dialing Calls

To dial a call, connect your analog telephone line(s) to the RJ-11 phone
line jacks on the side of the unit. With the Monitor rotary selector switch,
select the phone line you wish to dial. Press the Add button to take the
selected Monitor line off-hook. The selected Monitor line LED indicator
will light green. You may now dial the call with the DTMF keypad. All
transmit sources, as well as the input signal from the hybrid, will be
muted while DTMF tones are being transmitted into the phone line.

* If the LED lights red when the add button is pressed, this means that
there is no active phone line connected to the corresponding RJ-11 jack.

Answering Calls
You will be alerted to an incoming call with an LED visual ring indicator
for that line. When you are receiving an incoming call, the correspond­ing line LED will flicker green. To answer this call you must first select
the corresponding line with the Monitor rotary selector switch. You may
then answer the call by pressing the Add button. The corresponding line
LED will now light constant green.

NOTE: There is no audible ringer on the Four IFB.
Dropping Calls

To drop an active call you must first select the corresponding phone line
with the Monitor rotary selector switch. Pressing the Drop button will
now disconnect the call on the selected Monitor phone line. The corre­sponding line LED will now become unlit.

Operator Communication
You may send and receive audio through a handset connected to the
Monitor handset jack and/or through the Monitor XLR line input and out­put. Audio from the handset and the Monitor XLR input will be sent
down the currently selected Monitor line as well as any IFB output se­lected to the same line. Audio from the Monitor phone line will be sent
into the Monitor handset and the Monitor XLR output.

Example:
Phone line 1 is selected as Monitor via the Monitor rotary selector
switch.
IFB 1 and IFB 2 rotary selector switches are set to line 1.
IFB 3 and IFB 4 rotary selector switches are set to line 2.

Audio from the telephone handset microphone and from the Monitor
XLR input will be sent down phone line 1 and out of the Monitor XLR
output, handset speaker, IFB 1 XLR output and IFB 2 XLR output.

14

Operation (continued) Operation

Audio from phone line 1 will be sent to the telephone handset speaker,
Monitor XLR output, IFB 1 XLR output and IFB 2 XLR output.

IFB 3 and 4 XLR outputs will contain audio from phone line 2 (if active).
Power Loss

Four IFB provides the option of using a 9VDC battery as backup to AC
power. If AC power is lost, the 9VDC battery will become the active
power source until AC power is restored.

FAQ’s

? Can I connect a microphone to the input?
! No, the Monitor Send XLR input is a line level input so you cannot

use a microphone without a pre-amp. This input is for connection of a
line level audio signal only

? If I have the unit plugged in to an AC power source while I am

using it, will it recharge the battery?

! No, this device does not have a rechargeable battery. You should

only use an alkaline battery. Battery life will depend on how many
devices are connected and how the unit is being used.

? Can I talk to all four IFB outputs at the same time?
! No, the Monitor handset and Monitor Send XLR inputs can only be

connected to one IFB output at a time, using the Monitor selector
switch.

? I hear the called party on the handset but they can’t hear me.
! This unit was designed to work only with an electret-type handset.

Try using an AT&T, Sony or Lucent handset.

? Can I use the Four IFB to conference the phone lines together?
! No, the telephone lines cannot be bridged together on this device.

? How does each IFB line talk to the monitor?
! The IFB connectors are listen only. The four IFB outputs can be set

to receive audio from any of the four telephone lines but they cannot
send audio. Only the Monitor handset (or line level input from your
mixer, etc) can talk to the called parties on the telephone lines or to
the IFB outputs.

.

15

Simplified Block Diagram

XLR Output

Input

XLR

Keypad

DTMF

4

and Hybrid

Hold relay

3

and Hybrid

Hold relay

2

and Hybrid

Hold relay

1

RJ-11

and Hybrid

Hold relay

Monitor Section

Selector

Monitor

Selectors

Line

12-2-2005

Simplified Block Diagram

JK Audio , Inc.

Four IFB

Level Controls

Out puts

XLR

4

3

2

1

16

Operation (continued) Specifications

Inputs:

Line: Balanced Female XLR, 20k ohm,
+4 dBu max

Outputs:

Line: (5) Balanced Male XLR, 600 ohm,
Line level, +4 dBu max

Handset: RJ-22 handset jack biased for
electret handset (not included)

Phone Line: (4) RJ11C
Isolation: 1500 VAC
Ringer: 0.4B REN
Frequency Response: Telephone Side 200 - 3600 Hz
Power: 120-240 VAC, 50-60 Hz

Internal power supply

Auxiliary Power Single 9 VDC battery
Size: 10" x 9.75" x 2"
Weight: 3.5 pounds

17

FCC Part 15 Compliance

This equipment has been tested and found to comply with the
limits for a Class A digital device, 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.

Changes or modifications not expressly approved by JK Audio
can void the user's authority to operate the equipment.

FCC Registration

Your new JK Audio product has been registered with the
Federal Communications Commission (FCC). This product
complies with the standards in Part 68 of the FCC rules.

1. Connection and use with the nationwide telephone
network

The FCC requires that you connect this telephone

equipment to the national telephone network through a
USOC RJ-11C modular telephone jack.

This equipment may not be used with Party Line Service or

Coin Telephone Lines

This equipment is hearing aid compatible.

2. Information for the telephone company

Upon request from your local telephone company, you are

required to provide the following information:

a) The "line" to which you will connect the telephone

equipment (that is, your telephone number), and

18

FCC Registration

b) The telephone equipment's FCC registration number.

This can be found on the bottom of your telephone

equipment, and,
c) the ringer equivalence number (REN) for this equipment.
The REN is used to determine the quantity of devices which
will be connected to the telephone line. Excessive RENs on
the telephone line may result in the devices not ringing in
response to an incoming call. In most, but not all areas, the
sum of the RENs should not exceed 5.0. To be certain of the
number of devices that may be connected to the line, as
determined by the total RENs, contact the local telephone
company.

3. Repair Instructions
If it is determined that your telephone equipment is

malfunctioning, the FCC requires that it not be used and
that it be unplugged from the modular outlet until the
problem has been corrected. Repairs to this telephone
equipment can only be made by the manufacturer or its
authorized agents or by others who may be authorized by
the FCC. For repair procedures, follow the instructions
outlined under the warranty section of the manual.

4. Rights of the telephone company

If telephone equipment is causing harm to the network, the

telephone company may temporarily discontinue your
telephone service. If possible, they'll notify you before they
interrupt service. If advanced notice isn't practical, you'll be
notified as soon as possible. You'll be given the opportunity
to correct the problem, and you'll be informed of your right
to file a complaint with the FCC.

Your telephone company may make changes in its

facilities, equipment, operations or procedures that could
affect the proper functioning of your JK Audio product. If
such changes are planned, you'll be notified by your
telephone company.

19

Warranty

Four IFB is covered by a 2-year warranty to be free from
defective workmanship and materials. In the event that the
Four IFB needs repair, you must call us to get an
authorization, and then carefully pack and ship it to us. You
will pay for shipping to us and we will pay for return back to
you, UPS ground. No free repairs will be made if the defect
was caused by misuse, weather conditions, or other cause,
except for defective workmanship or materials.

THERE ARE NO EXPRESSED OR IMPLIED
WARRANTIES WHICH EXTEND BEYOND THE
WARRANTY HERE MADE.

10/06

JK Audio, Inc. 1311 E 6th Street, Sandwich, IL 60548 USA

Voice: [phone] Toll Free: 800-JK-Audio Fax: [phone]

[e-mail] www.jkaudio.com

Copyright © 2006 JK Audio. All Rights Reserved.