JK Audio Four IFB - Manual (Page 3)

3
Introduction
Four IFB is a four position analog telephone line interface de-
signed 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 independ-
ent volume controls.
Individual on-hook/off-hook function for each phone line is con-
trolled by the Monitor Add and Drop switches. The phone line to
be controlled with these switches is determined by the Monitor ro-
tary 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 con-
trols and components are dust and moisture resistant. A non-
removable 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.