Technical Manual

6-14
Figure 14 Control Top Flex
Volume control is also provided by S1, which contains a
potentiometer biased between +5Vdc and ground. The VOL signal is a
voltage level between +5Vdc and 0Vdc, dependent on the position of
the rotary knob. VOL is an input to an A/D port on the MCU (U701).
The MCU sends the appropriate message to the DSP to adjust speaker
volume based on this setting.
Switch S2 is the three-position, programmable toggle switch typically
used for expanded zone/channel selection. It is an input to an MCU
A/D port with levels of 0Vdc, 2.5Vdc, and 5Vdc.
Programmable top (orange) button SW3 is typically used for
emergency. This button, along with programmable side buttons SB1
through SB3, is connected to a resistor divider network, biased
between +5Vdc and ground. This network, made up of R1, R2, and R3,
provides a voltage level, controlled by which button is pressed, to an
A/D port on the MCU. The MCU determines which button has been
pressed based on the value at the A/D port.
LED D1 is the TX/RX indicator. LEDs D2 through D6 are used for
backlighting the frequency knob.
R1
91K
R3
150K
SB1
(MON)
SB2
S2
TOGGLE
SWITCH
SB3
SW3
TOP BUTTON
SW2
PTT
1
2
2
4
3
1
D1
+5V
4
8
B
U1
Zone/Channel
Select
C
C
A
R901
S1
VOL
S901
ON/OFF
1
2
3
45
UNSW_B+ (33)
+5V (35)
TOGGLE SWITCH (TG1)
(34)
VOL (31)
* EMERG (14 or 41)
B+_SENSE (32)
GREEN_LED (22)
RED_LED (21)
INT_PTT* (38)
RTA0 (27)
RTA1 (24)
RTA2 (26)
RTA3 (25)
SECURE/CLEAR (TG2)
SWITCH (23)
DGND (15)
BL_EN (20)
BL_HOME (19)
INT_SPKR (40)
SPKR_COM (37)
INT_MIC (36)
AGND (39)
1
2
To Controller
J101
R2
68K
MAEPF-26006-A
2
4
3
1
D2
2
2
4
3
1
1
LS1
MIC
2
C1
1
D4
2
4
3
1
3
1
3
1
D5
2
4
D3
2
4
D6
+5V
+5V
* NOTE: EMERG line is on pin 41 for controller NCN6128_
and on pin 14 for controller NCN6167.