Midian Encryption Programming and Service Manual
TM8000 Encryption
49
June 2006
© Tait Electronics Limited
Q1 to Q5 are level translators for interfacing between the TM8000 3V3
logic on GPIO (pins 3 to 7) and the module’s 5V logic. Q1, Q2, Q4 and
Q5 are on the code space lines and Q3 is on the Mode line.
Wake-up Circuit
Comparator circuitry U2 and associated components provides a wake-up
signal for modules with a low current (sleep) mode. This signal is derived
from RSSI voltage exceeding a fixed level (set by R13 and R18). U5 acts as
an inverter and the wake-up circuit links to the module via Link 1 (1-2). See
“Link Setting” on page 51
for more information.
RS232 Buffer (future development)
U3 and associated components provide an RS232 buffer for module
programming.
Filtering
All signals passed through SK1 are filtered by FL1 through to FL4.
Alternate functions
As Midian TVS-2 modules only require a two-bit code, GPIO6 and GPIO7
are available for alternate functions via Links 7 through 10. (Note: links are
normally set for GPIO6 and GPIO7 to CS4 and CS8).
SK102 Functions for
GPIO6 and GPIO7
IOP_GPIO6 CS4 / WAKEUP / INDICATOR FROM MODULE
IOP_GPIO7 CS8 / WAKEUP / INDICATOR FROM MODULE
TM8000 Internal Options connector (SK102) 18way Micromatch Socket
Pin
Signal
Description
Signal Type Levels
Conditions
1
13V8_SW
Switched 13.8v supply (switched)
Power
13.8V
2
AUD_TAP_OUT
Programmable TAP OUT, DC coupled
Analogue
0.69Vp-p
600 ohms
3
AGND
Analogue ground
Ground
4
AUX_MIC_AUD Auxiliary microphone input (electret bias)
Analogue
7.5 mV
3.0 V Bias
5
RX_BEEP_IN
Receive sidetone Input, AC coupled
Analogue
0.76Vp-p
10 K ohms
6
AUD_TAP_IN
Programmable TAP IN, DC coupled
Analogue
0.69Vp-p
600 ohms
7
RX_AUD
Receive audio output post Vol, AC coupled
Analogue
1.0 Vp-p
100 ohms
8
RSSI
Analogue RSSI output
Analogue
.5-2.5 Vdc
1000 ohms
9
IOP_GPI01
Programmable Port, PTT OUT
Digital
3.3 V
CMOS
10
IOP_GPI02
Programmable Port, PTT IN
Digital
3.3 V
CMOS
11
IOP_GPI03
Programmable Port, Encry Mode ON / OFF
Digital
3.3 V
CMOS
12
IOP_GPI04
Programmable Port, CS 1
Digital
3.3 V
CMOS
