Studio Technologies 48 - Manual (Page 8)

Model 48 User Guide Issue 1, October 2000
Studio Technologies, Inc. Page 9
front-panel push-button switches. In some
applications it may be optimal to locate the
Model 48 directly adjacent to a Studio
Technologies’ Model 2 Central Controller.
If this is applicable, the Model 48 should
be mounted below the Model 2, allowing
optimal Model 2 cooling. The Model 48 is
secured to the equipment rack using two
mounting screws per side.
Earth Ground Connection
While it’s often likely that the mounting
screws holding a Model 48 into an equip-
ment rack will provide an earth ground
connection, this connection is not sufficient
for a satisfactory installation. A green-
colored screw, located on the Model 48’s
back panel, is provided so that a dedicated
earth ground connection can be made.
The interconnecting wire should be a
minimum of 14AWG and terminate on
a known “good” ground source.
Why is a separate earth ground connection
important? It helps ensure that stray volt-
ages appearing on the product chassis
are safely shunted to a ground point. Most
products utilize a mains power connection,
which generally includes a line, neutral,
and earth ground connection. But the
Model 48 is different. Being a completely
passive device, it doesn’t utilize a mains
power connection. While there is no direct
mains power connection, there is still the
chance hazardous voltages could enter
the unit by way of the source or destination
jacks. These voltages, such as those
caused by a lightening strike, could arc
over to the Model 48’s chassis and
present a potential safety issue. As such,
it is important that an earth ground con-
nection be made.
Modular Jacks
The Model 48 utilizes 6-position modular
jacks for source (input) and destination
(output) connections. These jacks are
typical to the telephone industry, allowing
up to six signals to be supported. De-
pending on the specific jack, two, four,
or six of the pins may be implemented in
the jack’s housing. The telephone industry
often refers to wiring as being organized
as pairs. Using this terminology a 6-posi-
tion jack can support one, two, or three
pairs of wires. Usually, only two or four
pins (one or two pairs) are implemented,
rather than all six pins. In a standard
“RJ11” arrangement, the middle two pins,
numbered 3 and 4, are used for the con-
nection of one telephone line. Refer to
Figure 2 for a description of the RJ11
arrangement.
Another standard wiring arrangement is
called “RJ14,” which supports one or two
telephone lines. It is implemented using
pins 2 through 5 of a 6-position jack. Refer
to Figure 3 for a description of the RJ14
arrangement.
Figure 2. RJ11 Jack Connections