CX261 Installation and User Guide v1.5
11
Front panel MP3 input
To facilitate easy connection of digital audio devices such as
portable MP3 players or laptop computers, a 3.5 mm stereo
jack socket is provided on the CX261’s front panel ([4] at
“Description of front panel” on page 8
).
The MP3 input replaces Line input 1, and will only operate
if the
MUSIC SOURCE
switch is set to L1/MP3. The front
panel
MP3
jack socket is selected instead of the rear panel
LINE 1
phono sockets by setting the
RCA/MP3
switch on
the rear panel ([4] at “Description of rear panel” on page 9
)
to MP3. A green LED on the front panel ([6] at “Description
of front panel” on page 8
) illuminates to confirm the
selection. When the MP3 input is selected, the music source
connected to
LINE 1
will no longer be available.
Microphone inputs
MIC 1
and
MIC 2
inputs are intended for the direct
connection of microphones. They are electronically balanced
and transformerless with an input impedance of greater than
2 kohms and optimised for use with microphones of 200 to
600 ohms impedance. The screw terminal input connectors
should be wired thus:
PIN
CONNECTION
1
Screen
2
Signal ‘-’ (cold)
3
Signal ‘+’ (hot)
Unbalanced microphones may be used by connecting pin 2
to pin 1 (cable screen) in the mating (male) screw-terminal
connector. 12 V phantom power is available, see “Phantom
Power” on page 15.
Each mic input may be routed to the main output at any
level. All microphone announcements automatically reduce
the music level in that zone while the announcement is in
progress; MIC 1 input also has priority over MIC 2 input
(see “Microphone Over Music Priority” on page 17 for full
details.)
Use of Mic 1 input with telephone system
MIC 1 input on the CX261 may be reconfigured to accept
an audio input directly from a compatible telephone system.
This permits announcements to be made from some (or any)
internal telephone extensions in a building. Not all telephone
systems are suitable for this application, and the system
documentation should be consulted in detail to ensure
compatibility.
In TEL mode, full galvanic isolation is provided between the
CX261 and the telephone system. The audio (or “paging”)
output of the phone system should be connected to the
MIC 1
input in the normal way. The impedance of the input in
TEL mode is 600 ohms; this should be suitable for the majority
of telephone systems. If the telephone system requires a high
input impedance, internal jumper J16 may be removed to
provide an input impedance of 48 kohms. See page 20 for
location of internal jumpers.
The
TEL GAIN
preset gain control ([10] at page 9
)
should be adjusted with a test call from the telephone system.
Note that the front panel
MIC 1 LEVEL
control is still
operational.
Paging Access Control
Access control for both microphone inputs is provided to
allow the CX261 to be interfaced to single-zone paging
mics such as the Cloud PM1. The access contacts work on
the short-to-ground system, which is compatible with the
majority of paging microphones.
The CX261 is shipped with the access control input disabled
for both microphone inputs. This allows immediate use with
standard microphones not fitted with PTT (Press-to-Talk)
switches. If external access control is required, the internal
jumpers J6 (Mic 1) and J7 (Mic 2) must first be removed. See
page 20 for location of the jumpers.
The access control input is a 3-pin 5 mm-pitch screw terminal
connector on the rear panel ([14] at page 9
). Mic input 1
becomes active when
M1
is connected to
0V
; Mic input 2
becomes active when
M2
is connected to
0V
.
0V M1 M2
Activate Mic input 1
Activate Mic input 2
Part of external
paging mics
Access contacts
See also the section “Priorities” for further information on
the use of the CX261 with paging microphones.
