Maxon SD-160 Series User manual

SD-160 Series Data Radio
(include SD-170 Series)
Technical Manual

2
TABLE OF CONTENTS
1. INTRODUCTION................................................................... 4
2. TECHNICAL SPECIFICATIONS ....................................... 5
3. FEATURES ............................................................................. 9
4. THEORY OF OPERATION ............................................... 23
4.1. INTRODUCTION ...........................................................................23
4.2. DIGITAL CIRCUITS ......................................................................23
4.3. RF CIRCUITS.................................................................................27
4.3.1. PLL SYNTHESIZER ................................................................................ 27
4.3.2. TRANSMITTER ....................................................................................... 28
4.3.3. RECEIVER .............................................................................................. 29
4.4. ACC-513 (GMSK MODEM CIRCUITS)........................................31
4.5. ACC-514 (FFSK MODEM CIRCUITS) .........................................32
4.6. ACC-515 (GPS INTERFACE CIRCUITS) .....................................33
5. MAINTENANCE AND REPAIR ........................................ 34
6. COMPONENT REPLACEMENT ...................................... 38
7. ALIGNMENT PROCEDURE ............................................. 40
7.1. RECEIVER...................................................................................... 41
7.2. TRANSMITTER ..............................................................................42
7.3. SQUELCH ADJUSTMENT ............................................................43
7.4. TEST EQUIPMENT SETUP ..........................................................45

3
8. INTERFACING .................................................................... 47
8.1. External connections ......................................................................47
8.2. DB-15 PIN descriptions with input/output level ............................47
8.3. Internal components ....................................................................... 49
8.4. Option board pin-out chart ............................................................50
8.4.1. ACC-513 (GMSK Modem Option board)................................................ 50
8.4.2. ACC-514 (FFSK Modem Option board) ................................................. 50
8.4.3. ACC-515 (GPS Option board) ................................................................ 51
8.5. Wiring Diagram.............................................................................. 52
9. TROUBLE SHOOTING GUIDE ........................................ 53
10. VOLTAGE CHART ........................................................... 60
11. ELECTRICAL PARTS LIST............................................ 65
11.1. PARTS LIST FOR SD-161 ............................................................ 65
11.2. PARTS LIST FOR SD-164 ............................................................ 72
12. COMPONENT PINOUT.................................................... 79
13. SCHEMATIC DIAGRAMS............................................... 83
14. CIRCUIT B’D DETAILS................................................... 93

4
1. INTRODUCTION
The SD-160 and SD-170 Series (hereinafter called “the radios”) of RF wireless
modems from MAXON utilize the latest technology in its design and manufacturing. Both
the UHF and VHF models are Phase Lock Loop Synthesizer (PLL) / microprocessor
controlled and offer two watts (SD-160 Series) or one to five watts (SD-170 Series) of
power with 16-channel capability. Multiple functions including 1200 to 9600 baud rates,
AC and/or DC audio coupling, GMSK, FFSK and FSK modulation are standard in these
fully programmable wide bandwidth RF wireless modem units. Programmable sub-audio
squelch system (CTCSS & DCS) and two-tone squelch system are newly added to the
signal level detect squelch system (RSSI). GPS Data handling is provided to interface
and control internal GPS receiver.
The radios are programmed using an IBM® Personal Computer, DOS® or WINDOWS
®
based software, an interface module and a programming cable. This allows the radio to
be tailored to meet the requirements of the individual user and of the System(s) it is
operating within.

5
2. TECHNICAL SPECIFICATIONS
GENERAL
VHF UHF
Equipment Type : Data radio (Wireless Modem) Data radio (Wireless Modem)
Model Series : SD-161 SD-171 SD-164 SD-174
Performance Specifications : TIA/EIA-603 ETS 300-113 TIA/EIA-603 ETS 300-113
Frequency Range : 148-174MHz 148-174MHz 450-490MHz 450-490MHz
RF Output : 2W Only 1-5W 2W Only 1-5W
Channel Spacing : 12.5KHz, 25KHz Programmable
Modulation Type : F3D, F3E
Intermediate Frequency : 45.1MHz & 455KHz
Number of Channels : 16
Frequency Source : Synthesizer
Operation Rating : Intermittent
90 : 5 : 5 (Standby : RX : TX)
Power Supply : Ext. Power Supply (12 VDC Nominal)
Temperature Range :
Storage
Operating
From -40°C to +80°C
From -30°C to +60°C
Current Consumption :
Standby(Muted)
Transmit 5Watts RF Power
Transmit 2Watts RF Power
< 65mA
< 2.0 A
< 1.0 A
Lock Time : < 10ms
TX to RX attack time : < 20ms (No Power Saving)
RX to TX attack time : < 20ms
Dimensions : (32mm)H X (58mm)W X (125mm)D
Weight : 253 grams

6
TRANSMITTER
VHF UHF
Model Series : SD-161 SD-171 SD-164 SD-174
Carrier Power : (Nom. Max. Min.)
Hi Power
Low Power
2W < 3W > 1.5W
N/A
5W < 6W > 4.5W
1W<1.5W>0.8W
2W < 3W > 1.5W
N/A
5W < 6W > 4.5W
1W<1.5W>0.8W
Sustained Transmission :
Time : 5 10 30Sec
(Nominal Conditions)
Power : >90% >85% >80% Power : >90% >85% >80%
Frequency Error :
Nominal condition
Extreme condition
< 0.5 KHz
±5.0 ppm
< 0.75 KHz
±5.0 ppm
Frequency Deviation :
25 KHz Channel Spacing
12.5 KHz Channel Spacing
Peak ±5.0, Min. ±3.8
Peak ±2.5, Min. ±1.9
Audio Frequency Response : Within +1/-3dB of 6dB octave
@ 300 Hz to 2.55 kHz for 12.5 kHz C.S.
@ 300 Hz to 3.0 kHz for 25 kHz C.S.
Adjacent Channel Power :
25 KHz Channel Spacing
12.5 KHz Channel Spacing
< 70 dBc @ Nominal Condition , < 65 dBc @ Extreme Condition
< 60 dBc @ Nominal Condition , < 55 dBc @ Extreme Condition
Conducted Spurious Emission : < -60 dBc < -30 dBm < -60 dBc < -30 dBm
Modulation Sensitivity : 100mV RMS @ 60% Peak Dev.
Hum & Noise :
25 KHz Channel Spacing
12.5 KHz Channel Spacing
> 40 dB (without PSOPH)
> 40 dB (with PSOPH)
Modulation Symmetry : < 10% Peak Dev @ 1KHz input for nominal dev. + 20dB
Load Stability : No osc at ≥10:1 VSWR all phase angles and suitable antenna
No destroy at ≥20:1 all phase angle
Peak Deviation Range Adjustment
@ 1 KHz, Nom Dev + 20dB :
25 KHz Channel Spacing
12.5 KHz Channel Spacing
Min. 3.5, Max. 6.0
Min. 1.5, Max. 4.0

7
RECEIVER
VHF UHF
Model Series : SD-161 SD-171 SD-164 SD-174
Sensitivity (@ 12dB SINAD) :
25 KHz Channel Spacing
12.5 KHz Channel Spacing
< 0.28uV
< 0.30uV
< 0.28uV
< 0.30uV
< 0.28uV
< 0.30uV
< 0.28uV
< 0.30uV
Sensitivity ( 1/100 Error Rate)
With ACC-513
With ACC-514
< -113dBm
< -110dBm
< -113dBm
< -110dBm
< -113dBm
< -110dBm
< -113dBm
< -110dBm
Amplitude Characteristic : > -3dB , < +3dB > -3dB , < +3dB
Adjacent Channel Selectivity :
25 KHz Channel Spacing(Nom.)
(Extreme Condition)
12.5 KHz Channel Spacing(Nom.)
(Extreme Condition)
> 65 dB
> 55 dB
> 55 dB
> 45 dB
> 70 dB
> 60 dB
> 60 dB
> 50 dB
> 65 dB
> 55 dB
> 55 dB
> 45 dB
> 70 dB
> 60 dB
> 60 dB
> 50 dB
Spurious Rejection(100KHz ~ 4GHz) > 60 dB > 70 dB > 60 dB > 70 dB
Image / Half IF Rejection : > 60 dB > 70 dB > 60 dB > 70 dB
Intermodulation Response Rejection
±25 kHz/ 50 kHz
±50 kHz/ 100 kHz
> 60 dB
> 60 dB
> 70 dB
> 70 dB
> 60 dB
> 60 dB
> 70 dB
> 70 dB
Conducted Spurious Emission :
9 KHz - 1 GHz
1 GHz – 4 GHz
< -57 dBm
< -47 dBm
< -57 dBm
< -47 dBm
RX Spurious Emissions (Radiated) :
9 KHz - 1 GHz
1 GHz – 4 GHz
< -57 dBm
< -47 dBm
< -57 dBm
< -47 dBm
AF Distortion :
Nominal condition
Extreme condition
< 5%
< 10%
< 3%
< 10%
< 5%
< 10%
< 3%
< 10%
RX Hum & Noise (only audio) :
25 KHz Channel Spacing
12.5 KHz Channel Spacing
< 40 dB without PSOPH
< 40 dB with PSOPH
< 40 dB without PSOPH
< 40 dB with PSOPH
Receiver Response Time : < 16 ms < 16 ms
Squelch (factory pre-set)
Open
Close
-113dBm
-116dBm
Squelch Attack Time :
RF Level at Threshold
RF Level at Threshold + 20dB
< 20 ms (RSSI), < 40 ms (Analog)
< 10 ms (RSSI), < 30 ms (Analog)
Squelch Decay Time : 5 ms Min., 20ms Max.
Antenna Socket Input Match > 10 dB Return Loss
Temperature Stability for
L.O. Frequency :
1st < 5 ppm, 2nd < 15 ppm from -30° to + 60° C
L.O. Frequency Aging Rate : ±2 ppm/ year

8
REFERENCE CRYSTAL
VHF UHF
Model Series : SD-161 SD-171 SD-164 SD-174
Frequency : 12.8MHz
Holder Type : HC-18
Temperature Characteristic : ±5.0 ppm from -30° C to +60° C
Aging Rate : < 2 ppm/ year in 1st year
< 1 ppm/ year thereafter
ENVIRONMENTAL (performance without degradation unless stated)
VHF UHF
Model Series : SD-161 SD-171 SD-164 SD-174
Temperature (deg C)
Operating
Storage
-30° to +60° C Degradation Specified @ Extreme condition
-40° to +80° C
ESD 20 KV
Vibration MIL STD 810 C Procedures I, II, V and IEC68 26

Due to continuing research and development the company reserves the right to
alter these specifications without prior notice.

9
3. FEATURES
16 Channels
The SD-160 Series(include SD-170 Series, hereinafter called “SD-160”) radio can store up to 16
channels within the same band. These channels can be selected by inner DIP-S/W or serial
command inputted from external control system.
Channel Spacing
The SD-160 is capable of programmable channel spacing, in both UHF and VHF bands. Each
channel can be programmed via the PC programmer, ACC-916, having 12.5KHz or 25KHz
channel spacing.
Output Power
In case of SD-160, 2-Watts output power is only available, but, in SD-170, it’s programmable.
Each channel can be programmed via the PC programmer to a high-power output, 5 Watts, and
a low-power output, 1 Watt.
Channel Scan
For audio application, SD-160 supports channel scan enabled via serial commands. During
programming of the radio, any channel can be selected as a scanned channel. When a scanned
channel is selected, it becomes a part of the scan list. Once the scan list has been established,
initiates scan by serial commands. If a conversation is detected on any of the channels in the
scan list, the radio will stop on that channel and audio signal will be released through pin 9 of
the DB-15 connector. At that moment, busy channel data is sent to external equipment or
device through serial command. So, busy channel data can be identified as decoding received
serial command from radio in the external equipment or device. Normally, if user tries to transmit
during scanning, the transmission will be made on the channel that the call is received during
the programmable scan delay time. (The scan delay time is the amount of time the radio will
stay on that channel once working has ceased. Dealer programming of 4 ~ 7 seconds is typical).
The radio will resume scanning once the scan delay time has passed, and will continue to scan
until the serial command for scan stop is inputted by external equipment. After the scan has
resumed, if a transmission is made, the radio will transmit on the selected priority channel. This
feature is similar to priority scan TX except for selection of priority channel. You can assign a
priority channel by inner dip switch only.

10
Scan Delete
To temporarily delete a channel from the scan list, simply input the serial command for scan
deletion to the radio while scanning and stopped on the channel to be deleted. This will
temporarily remove that channel from the scan list until the scan is closed or the radio’s power is
reset.
CTCSS / DCS Scanning
To help to block out unwanted calls to your radio, the SD-160 series can be programmed by
your dealer to scan for tones.
Busy Channel Lockout
This feature, when enabled, disables the transmitter when the user would attempt to transmit
during the receiving channel is busy. It will be dealer-programmable on/off and applicable to all
channels.
Marked Idle
When used in conjunction with Busy Channel, lockouted transmitter is allowed to operate as
long as valid RX tone is received. Dealers program this feature as ON or OFF. This feature will
be dealer-programmable on/off and applicable to all channels.
TX Time-out
This feature, when enabled, limits the amount of time that the user can continuously transmit.
This time can be set in increments by 10 seconds from 10 seconds to 990 seconds. If the user
attempts to transmit longer than the TX Time-out period, five seconds prior to expiration, the
radio will release Time-out alert signal through pin 9 of the DB-15 connector and will cease
transmission.
Power Save
The function of Power Save is used when an external battery is used as the power source.
When Power Save is enabled, the receiver ON and OFF time can be programmed and allows
the operator to set the length of time the receiver gets asleep.
Tx Delay
The TX will remain active for 150 ms at the end of TX when using CTCSS tones. This eliminates
squelch tail. Dealer programs this feature as ON or OFF.

11
Squelch Options
Compared to existing Maxon data radios, programmable sub-audio squelch system (CTCSS &
DCS) and two-tone squelch system are newly added. Each channel will have these squelch
option sets during dealer programming. More detail descriptions for all available squelch
systems of SD-160 are the following.
Sub-audio squelch system
The SD-160 can operate singly or with optional modem boards. Even if user wants to use sub-
audio SQ system, the radio will permit this SQ option according to some cases to avoid
confliction between sub-audio and data.
Contrary to general-purpose two-way radio, the input of the radio is data or audio. In case of
audio, its frequency spectra are limited to 300㎐∼3㎑by internal BPF. So, the division of this
and sub-audio is possible on the frequency spectra because sub-audio has under 300㎐
frequency. But, Data has wide frequency spectra compared with audio. Normally, that has 30㎐
∼4.8㎑frequency (except harmonic freq.) at 9600 baud rate. Accordingly, the conflict of sub-
audio and data are inevitable and so broken data or SQ error is unavoidable. To solve this
problem, the radios can use the FFSK modulation which converts data into two different
continuous audio tone according to their logic levels. Therefore, available cases of sub-audio
SQ system are Audio and FFSK signal. But, it’s not permitted to FSK(FM direct modulation of
data) and GMSK signal.
a.Single operation of SD-160
If the radio operates singly, only FM direct modulation/demodulation of audio and data are
available. In this case, audio and data are inputted and released through different DB
connector lines which pin 7, 9, 1 and 2 of DB-15 connector are used as audio input, audio
output, data input and data output, respectively. Normally, Sub-audio Squelch(SQ) System
can be applied to audio signal, but data doesn’t use it to avoid frequency confliction. So, if
user tries to transmit data in one channel which has sub-audio squelch option, radio will
flash green LED two times as warning and then transmit it without sub-audio.
Note : SD-160 provides the connection of external modems to receive and transmit
external modulated data which can be inputted and outputted through pin 1 and 2

12
of DB-15 connector, respectively. In this case, the external signals are referenced
to ground and may be a.c. or d.c. coupled depending on the user requirement.
Especially, if the type of external modem is AFSK or FFSK, Sub-audio
Squelch(SQ) System can be applied by dealer programming. For reference, its
related parameter is “Tx Tone Generation for Data Input” of “Tx option” group
on the “System Option / GPS” tap window of ACC-916.
Brief block signal flow diagrams for each input are the following (See Figure 2.1. ~ 2.3.).
Audio signal flow in Transmitter
Pre-emphasis
Audio Amp. & Filter
Level
Detector
300Hz HPF
Analog S/W
MC14053B
Data BPF
Sub-Audio LPF
MF6
Z1 Z
Y1 Y
Adj. Level
MCU
Check Audio In
Tone En
Audio In
Mod Out
Sub-Audio
Encoder
Y0
Z0
X1 X
X0
High : Audio In
Low : No Audio
300Hz HPF
Analog S/W
MC14053B
Sub-Audio LPF
MF6
Z1 Z
Y1 Y
MCU
Audio Mute
Y0
Z0
X1 X
X0
Pre-Selector
RF Board
Sub-Audio LPF
4th Order
AF
IF IC
TA31136FN
RSSI
Audio Amp.
Comparator
MF6
Audio Mute
Tone Detector
RSSI
Audio Out
LM386
Busy
Audio signal flow in Receiver
Figure 3.1. Audio signal flow diagram
Level
Detector
Data BPF
MCU
Check Audio In
Data Enable
Audio In
Mod Out
Data In
High : Audio In
Low : No Audio
If audio input is absent,
Data path will be enabled.
In this case,
Sub-audio option is ignored.
Data signal flow in Transmitter
RF Board
AF
IF IC
TA31136FN
RSSI
Data
Out
BPF
30Hz ~ 5KHz
MCU
RSSI
Busy
Comparator
Data signal flow in Receiver

13
Figure 3.2. Data signal flow diagram
Ext. Mod. signal flow in Transmitter
Level
Detector
Analog S/W
MC14053B
Data BPF
Sub-Audio LPF
MF6
Z1 Z
Y1 Y
Adj. Level
MCU
Check Audio In
Tone En
Audio In
Mod Out
Sub-Audio
Encoder
Y0
Z0
X1 X
X0
High : Audio In
Low : No Audio
Data Enable
Data In
Analog S/W
MC14053B
Sub-Audio LPF
MF6
Z1 Z
Y1 Y
MCU
Y0
Z0
X1 X
X0
Pre-Selector
RF Board
Sub-Audio LPF
4th Order
AF
IF IC
TA31136FN
RSSI
Comparator
MF6
Tone Detector
RSSI
Audio Out
Busy
Ext. Mod. signal flow in Receiver
BPF
30Hz ~
5KHz
Figure 3.3. External modulated signal flow diagram
b. FFSK & GMSK
Maxon provides two optional modem boards, ACC-513, GMSK and ACC-514, FFSK for
SD-160 to improve the efficiency for data transmission and offer maximum flexibility for
user application. Selection of the required modulation option is made installing wanted
modem to radio and programming several modem parameters through PC-programmer,
ACC-916. Modem board provides the facility to connect a computerized controller via an
RS-232 level serial data interface (i.e. Communication port COM1, COM2, etc. for PCs) to
its Slave MCU. Received data from controller(DTE) will then drive the FFSK or GMSK
modulator and allow transmission of serial data. It also provides FFSK or GMSK
demodulator for the reception of FFSK or GMSK modulated data signals. These are
converted to RS-232 level serial data stream for supply to a computerized controller.
In application of Sub-audio squelch, it can’t apply to GMSK modulated signal because of
their frequency confliction. But, FFSK modulated signal can be mixed with sub-audio
because it consists of two different continuous tones which frequency spectra are on the
audio frequency region.
Brief block signal flow diagrams for each optional modem board are the following (See
Figure 2.4. and Figure 2.5.).

14
Analog S/W
MC14053B
Sub-Audio LPF
MF6
Z1 Z
Y1 Y
Adj. Level
Master MCU
Tone En
Mod Out
Y0
Z0
X1 X
X0
Sub-Audio
Encoder
Serial Data In Serial Data In
(CMX469A)
FFSK Modem
Option Board
Tx_CLK
Rx_CLK
Tx_Data_Out
Rx_Data_In RDI
RxC
TDO
TxC
Tx_Signal
Slave MCU
Tx_En
Rx_En
Data BPF
Analog S/W
MC14053B
Sub-Audio LPF
MF6
Z1 Z
Y1 Y
Master MCU
Y0
Z0
X1 X
X0
Pre-Selector
RF Board
Sub-Audio LPF
4th Order
AF
IF IC
TA31136FN
RSSI
Comparator
MF6Tone Detector
RSSI
Busy
Serial Data Out Serial Data Out
(CMX469A)
FFSK Modem
Option Board
Tx_CLK
Rx_CLK
Tx_Data_Out
Rx_Data_In RDI
RxC
TDO
TxC
Rx_Signal
Slave MCU
Tx_En
Rx_En
FFSK signal flow in Transmitter FFSK signal flow in Receiver
Figure 3.4. FFSK signal flow diagram
Data BPF
Master MCU
Mod Out
Sub-audio option is ignored.
Serial Data In Serial Data In
(CMX589A)
GMSK Modem
Option Board
Tx_CLK
Rx_CLK
Tx_Data_Out
Rx_Data_In RDI
RxC
TDO
TxC
Tx_Signal
Slave MCU
Tx_En
Rx_En
RF Board
AF
IF IC
TA31136FN
RSSI
RSSI
Busy
Serial Data Out Serial Data Out
(CMX589A)
GMSK Modem
Option Board
Tx_CLK
Rx_CLK
Tx_Data_Out
Rx_Data_In RDI
RxC
TDO
TxC
Rx_Signal
Slave MCU
Tx_En
Rx_En
Master MCU
GMSK signal flow in Transmitter GMSK signal flow in Receiver
Figure 3.5. GMSK signal flow diagram

15
c. CTCSS signal information
Each channel supports the 38 TIA/EIA standard tone frequencies and 11 non-standard
tones. All tones will be set up during dealer programming.
No. Freq.
(Hz)
No. Freq.
(Hz)
No. Freq.
(Hz)
No. Freq.
(Hz)
No. Freq.
(Hz)
01 67.0 11 97.4 21 136.5 31 192.8 41 171.3
02 71.9 12 100.0 22 141.3 32 203.5 42 177.3
03 74.4 13 103.5 23 146.2 33 210.7 43 183.5
04 77.0 14 107.2 24 151.4 34 218.1 44 189.9
05 79.7 15 110.9 25 156.7 35 225.7 45 196.6
06 82.5 16 114.8 26 162.2 36 233.6 46 199.5
07 85.4 17 118.8 27 167.9 37 241.8 47 206.5
08 88.5 18 123.0 28 173.8 38 250.3 48 229.1
09 91.5 19 127.3 29 179.9 39 69.3 49 254.1
10 94.8 20 131.8 30 186.2 40 159.8
Table 3.1. CTCSS Frequency Chart
d. DCS signal information
The radio supports the encoding and decoding of 104 DCS data (include TIA/EIA code).
Octal
Code
Octal
Code
Octal
Code
Octal
Code
Octal
Code
Octal
Code
Octal
Code
Octal
Code
Octal
Code
Octal
Code
Octal
Code
023 054 125 165 245 274 356 445 506 627 732
025 065 131 172 246 306 364 446 516 631 734
026 071 132 174 251 311 365 452 523 632 743
031 072 134 205 252 315 371 454 526 654 754
032 073 143 212 255 325 411 455 532 662
036 074 145 223 261 331 412 462 546 664
043 114 152 225 263 332 413 464 565 703
047 115 155 226 265 343 423 465 606 712
051 116 156 243 266 346 431 466 612 723
053 122 162 244 271 351 432 503 624 731
Table 3.2. DCS Code Chart

16
Two-Tone Squelch(SQ) System
The radios will support Motorola-Format, Two-Tone(Type 99) decoding. This is receive only,
decode only feature. It will allow a dispatcher to call individuals and groups. Each
System/Group will be programmable to respond to any combination of the code, with a
distinctive alert for each System/Group. The alert format consists of two tone sequences, first
the ID of the radio being called, then the ID of the calling radio.
This feature is programmed by the dealer(per customer’s request) and is not activated /
deactivated by the user. The user interface consists of the radio emitting the tones being
broadcast. At this point, the radio will enter Unmuted Rx mode and remain in this mode until the
PTT signal is inputted.
Serial command
To give the simplest protocol for control of radio, Maxon has prepared for some serial
commands which have an ease to encode and decode format. SD-160 can be used without
serial commands, but user can use its various functions through application of those, for
instance, setting-up the basic radio operation such as channel change, switch of RX/TX and
channel scan, moreover, used for control of GPS and modem option board. All messages are in
binary format, which reduces required data size to shorten response time of radio and follows
below data format.
Serial RX/TX Data Format
(1) Asynchronous Serial Data Transfer
(2) Baud Rate : 4,800 bit/sec
(3) Data Bit : 8bit , Non Parity
(4) Stop Bit : 1bit
(5) MSB first transmission
Each serial command is consist of 3 bytes. 1st byte is command and 2nd is data required by
command and 3rd is check sum to decide validity of total contents.
Byte0
ST 1st Byte (Command) SP
Byte1
ST 2nd Byte (Data) SP
Byte2
ST 3rd Byte (Check Sum) SP

17
Data Protocol
a. Protocol for input serial command
Protocol of data transmission from external equipment or device (: PC) to radio :
Input serial command
Receive response
Response
External equipment or device Radio
Figure 3.6. Protocol for input serial command
b. Protocol for output data
Protocol of data transmission from radio to external equipment or device (: PC) :
Receive Data
Receive Data
Output Data
(with command)
External equipment or device Radio
Output Data
(with command)
Figure 3.7. Protocol for output data
Detail information of Serial Commands
a. Transmitting Command & Data
Mode Command
(BYTE0)
Data
( BYTE1 )
Check sum ( BYTE2 )
: Command + Data

18
1. Channel Change 0x64 0x?? :Current channel ( 0x64 + Channel )
2. RTX Mode Selection 0x61 R(0x72) : Rx mode
T(0x74) : TX mode
( 0x61+0x72 )
( 0x61+ 0x74 )
From PC
To Radio
0x62 F(0x46) : Scan Stop
S(0x73) : Scan Start
O(0x4F) : Scan Delete
( 0x62+ 0x46 )
( 0x62+ 0x73 )
( 0x62+ 0x4F )
From Radio
To Pc
0x66 0x00 : 1 Channel
0x01 : 2 Channel
0x02 : 3 Channel
M
0x0f : 16 Channel
0x66 + 0x00
0x66 + 0x01
M
*Only for Unmute Channel,
Correct Call Channel
3.
Scan Mode
Error
Message
0x65  It occurs when Scan Delete command comes except
Busy/Correct Call
 It occurs when PTT key is pushed except
Busy/Correct Call.
 It occurs when channel change command exists
during Scanning.
Control of
GPS Power
0x6a 0x00 : GPS Power Off
0x01 : GPS Power On
( 0x6a + 0x00 )
( 0x6a + 0x01 )
4.
GPS
mode Control of
GPS Data
0x63 0x00 : GPS Data Disable
0x01 : Release GPS Data
to DB-15
0x02 : Release GPS Data
to Modem
( 0x63 + 0x00 )
( 0x63 + 0x01 )
( 0x63 + 0x02 )
5. Modem test mode 0x75 0x78 : Enable test data
0x79 : Disable test data
( 0x75 + 0x78 )
( 0x75 + 0x79 )
GMSK 0x7a 0x00 : Disable
0x01 : Enable
( 0x7a + 0x00 )
( 0x7a + 0x01 )
0x7c 0x00 : Disable
0x01 : Enable Mark data
( 0x7c + 0x00 )
( 0x7c + 0x01 )
6.
Modem
alignment
mode FFSK 0x7e 0x00 : Disable
0x01 : Enable Space data
( 0x7e + 0x00 )
( 0x7e + 0x01 )
Table 3.3. Composition of input serial commands

19
Receiving Command & Data
Mode Command
(BYTE0)
Data
(BYTE1)
Check sum (BYTE2)
: Command + Data
0xaa ACK N/A1 Process Complete
Commands 0x55 NACK N/A
Table 3.4. Composition of response commands
Note)
This command is return signal for receiving command.
If Byte2 and sum of Byte0 and Byte1 among received data are same, Radio would
send ACK data and execute command. If not, Radio sends Nack data.
User would go into next step if receives ACK data. If receiving Nack data, user should
send command again.
example) If user changes from 1st Channel to 2nd Channel,
user should send Channel Change Command ( 0x64,0x02 , ( 0x64 + 0x2 ) ) to Radio.
If Byte2 and sum of Byte0 and Byte1 among received data are same, Radio sends
ACK data to user and goes to 2nd channel. If not, radio would send Nack data.
Status indicators and audible alert tones
SD-160 series data radio has a sophisticated microprocessor control which provides a range of
LED displays. LED displays operation mode, current status of radio, warning, and etc. Moreover,
if you connect the Speaker filtered OUT (Pin 9 of DB-15 connector) to an external speaker, you
can hear audible tones under the following conditions:
• Attempt to transmit on a channel which is already in use when busy channel lockout option
has been programmed
• Transmission time has exceeded time-out timer programmed length
• The other group or people has finished transmission using repeater
See the status indicators and audible alert tones chart (Table 2.5.) for full specification.

20
STATUS DESCRIPTION LED COLOR AUDIBLE TONE
POWER ON -
Busy Channel Yellow
Correct Call Green
Transmit Yellow
NORMAL
Transmit Not Allowed
Normal Scan Mode Green LED Flash
Scan Delete one time Red LED
SCANNING
Scan All Delete Two times Red LED
Busy Channel lockout two times Green LED Single Beep Tone
Time out Time one time Green LED
Before 5S T-O-T one time Green LED Single Beep Tone
EEPROM Error one time Yellow LED
Unlock Four times Yellow LED
Communication error with Modem
MCU
Green LED flash
Transmit Hang on time - Single Beep Tone
WARNING
Under channel programmed sub-
audio SQ, when transmission is
tried by input of FSK or GMSK
data.
Two times Green LED
Read Mode Red LED flash
PROGRAM Write Mode Green LED flash
AUTO TEST Yellow
Open Squelch Mode three times Green LED
Close Squelch Mode Two times Green LED
Save Squelch Mode One time Green LED
SQUELCH
PROGRAM MODE
Init Data Load one time Green LED
Table 3.5. status indicators and audible alert tones