Instruction manual

3-7
NOTE: Amplifier noise can be reduced by placing a jumper wire between the positive (+) and
negative (-) terminals of the Background Music Input (BGM) and/or the Telephone Page Input (TEL)
when these inputs are not in use. If the BGM is being used and the TEL is not, place a jumper wire on
the TEL input. If the TEL is being used and the BGM is not, place a jumper wire on the BGM input.
1. Connect Telephone Page Input (TEL) to TB5. See Figure 3-1, Section 5 on Page 3-2 for location.
Figure 3-6, below is an enlarged picture of the referred area.
2. Connect Night Ring Input (NR) to TB5. See Figure 3-1, Section 5 on Page 3-2 for location.
Figure 3-6, below, is an enlarged picture of the referred area.
NOTE: The Night Ring (NR) input requires a contact closure from the phone system to activate. The
NR must be connected to the phone line in the same room.
_
_
+
_
+
+
TB5
NR
TEL
BGM
Section 5
Night Ring, Telephone Page,
Background Music Connections
Figure 3-6
Ancillary Audio Input Connections
3. Connect Background Music Input (BGM) to TB5. See Figure 3-1, Section 5 on Page 3-2 for
location. Figure 3-6, above, is an enlarged picture of the referenced area.
WARNING: EXCESSIVE BGM VOLTAGE INPUT CAN CAUSE AMPLIFIER FAILURE. THE
PREFERRED AUDIO SOURCE OUTPUT FOR THE BGM INPUT OF THE SP40/2 (CD PLAYER,
TUNER, EQUILIZER, ETC.) SHALL BE A FIXED LINE LEVEL VOLTAGE LESS THAN 2.5V PEAK
TO PEAK OR 300mV RMS. AUDIO SOURCES MARKED “LINE LEVEL OUTPUT” WILL
TYPICALLY BE WITHIN THIS LIMIT. AUDIO SOURCES WITH OTHER THAN FIXED LINE LEVEL
OUTPUTS (I.E., ADJUSTABLE SPEAKER OUTPUTS, ETC.) REQUIRE THAT THE AUDIO
SOURCE BE ADJUSTED USING A MULTIMETER ACROSS THE OUTPUT OF THE SIGNAL
SOURCE (SEE PROCEDURE BELOW). ONCE THE LEVEL HAS BEEN SET PROPERLY,
SECURE THE ADJUSTABLE AUDIO SOURCE SO THAT THE LEVEL CANNOT BE
INADVERTENTLY CHANGED. FAILURE TO SET ADJUSTABLE AUDIO SOURCES
APPROPRIATELY OR FAILURE TO SECURE AUDIO ADJUSTABLE SOURCES CAN LEAD TO
FAILURE OF THE AMPLIFIER SECTION OF THE SP40/2. THIS FAILURE, IN TURN, COULD
RESULT IN PROPERTY DAMAGE AND SERIOUS INJURY OR DEATH TO YOU AND/OR
OTHERS.
Setting Adjustable Audio BGM Sources for the SP40/2
NOTE: Use a good multimeter that provides true RMS readings in the AC voltage scale and
calculates the results through average sampling. Some multimeters can select instant or average
sampling readings. This adjustment shall always be done in the averaging mode. Most digital
multimeters use the average sampling method in the “AC Volts RMS” setting.
1. Insure that power is disconnected from the SP40/2.
2. Set Audio Source volume control to minimum setting.
3. Connect the Audio Source output to the BGM input terminals on the SP40/2.
4. Set the multimeter to the AC Volts scale, which is capable of reading 300mV RMS.