Theory of Operation
2 - 30
68P02963C70-O
Mode Select (OPTION1 and OPTION2)
Logic levels applied to the OPTION1, OPTION2, USB POWER, and AUDIO IN lines are
used to select the CE Bus mode. The modes will be set as follows:
MODE
OPTION_1
OPTION_2
USB_PWR
AUDIO_IN
NORMAL (no accessory)
1
1
0
X
USB Accessory/Computer
1
1
>4.0V
X
Dumb Accessory
1
0
X
1
Phone Powered USB Accessory
1
0
X
0
RS-232 (8 wire)/IDB Smart Cable
0
1
X
1
RS-232 (4 wire)/SSI
0
1
X
0
PTT
0
0
X
X
SB9600
X
X
Pin
No.
Signal Name (Short Form)
Power/
Default
States
USB
Dumb
RS232/
SSI
RS232
(8
wire)
1
Power Ground (GND)
GND
GND
GND
GND
GND
2
Battery Feedback (BATT_FDBK)
BATT_
FDBK
BATT_
FDBK
BATT_
FDBK
BATT_
FDBK
BATT_
FDBK
3
External Power (EXTB+)
EXTB+
EXTB+
EXTB+
EXTB+
EXTB+
4
USB+/TXD (D+)
D+
TXD
TXD
TXD
5
USB-/RXD (D-)
D-
RXD
RXD
RXD
6
USB Power/Ignition/RTS
(USB_PWR)
USB_P
WR
IGN
RTS
RTS
7
Switched Battery (SWB+)
SWB+
SWB+
SWB+
SWB+
SWB+
8
Hook Switch/CTS (HKSW)
HKSW
HKSW
CTS
CTS
9
MUTE/FS/DCD (MUTE)
MUTE
FS
DCD
10
DUMB_SEL2/SCK/RI (DSEL2)
DSCEN
DSCEN
DSEL2
SCK
RI
11
DUMB_SEL1/SRDA/DTR
(DSEL1)
DSEL1
SRDA
DTR
Summary of Contents for MTH500
Page 10: ...Contents x 68P02963C70 O THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 14: ...Foreword xiv 68P02963C70 O THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 18: ...Overview 1 4 68P02963C70 O THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 50: ...Theory of Operation 2 32 68P02963C70 O THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 76: ...Troubleshooting 3 26 68P02963C70 O Offset VCO Test ...
Page 78: ...Troubleshooting 3 28 68P02963C70 O This page left blank intentionally ...
Page 82: ...Programming the Radio 4 4 68P02963C70 O This page left blank intentionally ...
Page 100: ...Maintenance 5 18 68P02963C70 O Figure 23 Exploded View 1 2 3 4 5 7 6 X6 8 ...
Page 101: ...Maintenance 68P02963C70 O 5 19 Figure 24 Exploded View of Chassis Assembly 9 12 13 10 11 14 ...
Page 102: ...Maintenance 5 20 68P02963C70 O ...
Page 134: ...SCHEMATIC DIAGRAMS MTH500 Flex CD 6 32 68P02963C70 O This page left blank intentionally ...
Page 140: ...Replacement Parts and Kits 6 68P02963C70 O ...
Page 141: ...Replacement Parts and Kits 68P02963C70 O 7 ...
Page 142: ...Replacement Parts and Kits 8 68P02963C70 O ...
Page 144: ...Test Equipment Service Aids Tools A2 2 68P02963C70 O THIS PAGE INTENTIONALLY LEFT BLANK ...