Studio Technologies IFB Plus 2007 - Manual (Page 13)

Model 2 User Guide Issue 9, January 2006
Studio Technologies, Inc. Page 13
The Model 2 contains two telephone inter-
faces which can be individually configured
to allow connection to a telephone line or to
a standard audio signal. A telephone line is
designated as such if it has a DC bias cur-
rent associated with it. This type of signal is
sometimes referred to as a “wet” signal. A
standard audio signal is one that is isolated
from any source of DC voltage. Some fax
adapters associated with cellular telephones
provide this type of “telephone” line. A stan-
dard audio signal is sometimes referred to
as a “dry” signal. While this sounds confus-
ing, contemporary applications sometimes
refer to both types of signals as “telco.” To
a large production vehicle that pulls up to
do a two-week golf tournament, a telco line
is often one provided by the local telephone
company on an RJ11. To a mobile ENG
vehicle, a telco signal might come from a
cellular telephone which in most cases is a
standard audio signal.
Here is a review of the important features of
the Model 2’s telephone interfaces:
Interface 1
• Telephone line or standard audio mode
select switch on back panel
• Used to receive audio only
• Receive audio used as program and/or
VOX
source
• Front panel ±8 dB receive level trim pot
• Switch allows manual off-hook and
hang-up
(telephone line mode)
• Auto disconnect upon break in loop
current (telephone line mode)
• Operating mode and loop current status
LEDs
Interface 2
• Telephone line or standard audio mode
select switch on back panel
• Used to receive or send audio
• Receive audio used as program and/or
VOX
source
• Sends audio from either IFB channel
• Automatic answer of “ringing” telephone
line (telephone line mode)
• Auto disconnect upon break in loop
current (telephone line mode)
• Front panel ±8 dB receive level trim pot
• Switch allows manual off-hook and
hang-up
(telephone line mode)
• Operating mode and loop current status
LEDs
Setting the mode switches and connect-
ing signals is quite easy. Set the telephone
interface mode switches, located on the
back panel, to the desired mode—either
telephone line or standard audio signal.
Use modular telephone cables to mate the
Model 2’s modular jacks (RJ11-type) with
two more RJ11-type jacks. Technically, the
Model 2’s telco interfaces use 6-position
modular jacks with pins 3 and 4 utilized.
If the telephone line mode is selected, the
telco interfaces should, in most cases, termi-
nate on an access panel of some sort. This
will make rapid termination with telephone
company-provided lines. Because of the
presence of high voltage ringing signals, it
is best not to route tele-phone lines through
an audio patch bay.
If the standard audio mode is selected,
a direct connection to the source device
is acceptable, but connecting it via audio
patch points provides better flexibility. In the