FunkTronic Major BOS 2a2 User manual

Major BOS 2a2
Serial number 3799 or higher

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Table of Contents
Technical Data 2
Controls of Major BOS 2a2 3
Major BOS 2a2 4
Programming 4
Connectivity 4
Keypad 4
Carrier Indication (Squelch) 5
Transmitter Indication (PTT) 5
Selection Indication 5
Microphone Selection 5
Tone Call Decoder 5
Tone Call Encoder 5
Recording Conversations 6
Several Control Sets in Parallel Circuit 6
Operating in FMS mode 6
Functions for TETRA digital radios (SW version 1.02 or higher) 7
Potentiometers 8
Service Program 8
Registers of Major BOS 2a2 9
Reset to Factory Defaults 14
Sockets ST1 + ST2 for Junction Box 15
Board Layout 15
Connection Cable to PC 17
Board Layout (Junction Box MBOS2AB1) 18
Jumpers (Junction Box MBOS2AB1) 18
Pin Assignment (Junction Box MBOS2AB1) 19
Connectivity Scheme (with Junction Box MBOS2AB1) 19
Level of the Microphone 19
Board Layout (Junction Box MBOS2AB6) 21
Connectivity Scheme (with Junction Box MBOS2AB6) 22
General Safety Information 23
Returning of Old Equipment 23
Release Notes 24
Technical Data
Operating voltage +12V DC -15% +25%
Current consumption max. 1000 mA
AF input level
empfohlener Wert für Hörer-NF 500 mV (at 10 kohm)
Input impedance approx. 10 kohm
AF output level
Factory default 500 mV at 200 ohm
Setting range 300mV to 700mV
Output impedance (sending) approx. 200 ohm
Output impedance (receiving) high-impedance (disconnected)
Tape recorder output level
Factory default - 6 dBm (at 600 ohm)
Setting range (Potentiometer P8) - 14 dBm to - 2 dBm (at 600 ohm)
Output impedance approx. 600 ohm
Weight (without cable) approx. 1650 g
Size (without gooseneck microphone)
B x T x H 245 x 220 x 90 mm
Page

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Controls of Major BOS 2a2
12 3
6
7
8
12
11
4
10
9
5
1 - Transmitter indication (TX)
2 - Selection indication
3 - Receiver indication (Squelch, SQL)
4 - Selection key
5 - Monitoring volume
6 - PTT key
7 - Tone call key (Call 1 and Call 2)
8 - Master volume
9 - Loudspeaker (LS)
10 - PTT key handset
11 - Handset
12 - Gooseneck (GN) microphone

Major BOS 2a2
Major BOS 2a2 is a desktop radio controller intended to control radio systems with up to 4 radio circuits.
Operating parameters can be prgrammed from a computer using the configuration software.
Regarding functionality and connector pin assignment, Major BOS 2a2 compatible to Major BOS
2a.
Of course, there are several changes and new features:
- electrical, programmable potentiometers have replaced the analogous potentiometers
- programmable registers instead of jumpers
- programmable headset volume
- programmable amplification of the audio inputs from radio
- noise suppression for the inputs from radio
- tunable minimum volume for single radio circuits and tunable minimum overall volume
- AF settings (mute, listening, max. volume) can be adjusted separately for earpiece, loudspeaker,
and tape
- software option "NF-Squelch" (AF squelch)
- software option "Encoder/Decoder" permitted for up to four radio circuits
- flashing squelch LED and alarm tone on decoding of a call (call 1, call 2)
Programming
The Major BOS 2a2 can be configured using the Major BOS 2a2/2b2 programming software (download
at www.funktronic.de -> Service). Alternatively, the functions can be programmed directly in the
respective registers using a terminal program (e.g. hyper terminal).
The adjustment of the potentiometers, in general, is done using the terminal program.
Connectivity
The Major BOS 2a2 is connected to a 12V DC power supply unit. The control set is connected to a
junction box (MBOS2AB1/6), to which up to four radios can be connected. For each of the radios a
squelch input, a PTT output, a busy line as well as AF in- and output are available.
Depending on the version, up to 6 Major BOS 2a2 or Commander BOS2 can be connected to the
junction box.
Via a 25-pin D-Sub connector a headset or a FMS hand set can be connected.
For the recording of conversations a 6-pin DIN socket is available. As the AF outputs are only cut in
during transmission, i.e. are disconnected in idle or receiving mode, it is possible to operate several
Major BOS 2a2 in parallel circuit.
Keypad
The keypad consists of four selection keys for the different radio circuits, two tone call keys and the
red PTT key.

Carrier Indication (Squelch)
Every one of the four radio circuits provides its own carrier indicator (Squelch), which is located above
the corresponding selection key. If using junction box MBOS2AB1, for activation the squelch input
needs a voltage between 5V and 14V. If MBOS2AB6 is used, the logic of the carrier indication is
configurable. The polarity of the carrier indication and the AF muting when no carrier is present can
be programmed.
Transmitter Indication (PTT)
Every radio circuit has its own transmitter indication, which is lit when the transmitter is activated.
This happens upon pushing the PTT button or one of the two tone call buttons. The LED blinks if a
parallel Major BOS 2a2 is on transmission.
Selection Indication
The selection indicator is permanentely luminous if the corresponding radio circiut is selected and
active. If it is in blinking state this circuit is busy and cannot be selected.
Selection of Base Stations / Radio Circuits
To connect to one of the four radio circuits the corresponding selection key is to be pressed. A
subsequent button press sets the circuit to inactive. To activate more than one channel hold the first
pressed button down and select further circuits. Programming the Major BOS2a2 can disable this
feature. Acitve circuits are indicated by a luminous selection indication LED. A busy radio cuircuit is
idicated by a blinking LED. Radio circuits can be disabled, active radio circuits on power on can be
programmed.
Loudspeaker and Volume Control
On transmission the loudspeaker is turned off automatically. If it is off, when the handset ist lifted, can
be programmed. Loudspeaker volume can be adjusted with the master volume control.
Microphone Selection
The Major BOS2a2 has three microphone routings available. The PTT button in the handset turns
on the handset's microphone. The red PTT button and the headset's PTT input can be configured
independently. Possible associations are gooseneck microphone, headset microphone or automatic
selection. If automatic selection is on, the headset microphone is used if a headset is detected
otherwise the gooseneck microphone is used.
Tone Call Decoder
The optional software "Encoder/Decoder" allows the Major BOS2b2 to decode Tone Call1 and Tone
Call2 on any radio circuit and to activate the corresponding circuit automatically.
Tone Call Encoder

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The Major BOS 2b2 includes a encoder for Tone Call 1 and Tone Call 2. The tone calls are sent with
the corresponding keys of the keypad. The tone is sent as long as the button is pushed.
Recording Conversations
Via the installed tape recorder output the recording of conversations is possible. The interface
comprises a potential-free AF output as well as a potential-free contact (electronic relay) to control
a recording device.
Several Control Sets in Parallel Circuit
As the AF outputs are only cut in during transmission and the NF inputs are high-impedance, several
Major BOS 2a2 can be connected in parallel. To achieve this two configurations are possible:
a) If the junction box MBOS2AB1 is used, every Major BOS 2a2 is connected with his own box.
Subsequently, all connections to the radios (TX-AF, RX-AF, squelch and PTT keying) are connected
in parallel between the junction boxes.
b) If the junction box MBOS2AB6 is used, up to 6 control sets (Major BOS 2a2) can be connected
via one juction box.
Here, the busy-lines for the four radio circuits, that are only connected between the control sets, fulfil
a special task:
Every control set, that is connected to the busy-line, is able to recognize if the respective circuit is
already occupied by another control set (flashing of the selection indicator). An occupied circuit is
blocked and cannot be addressed by other control panels. All Majors can be muted while a busy-line
is active in order to avoid feedback.
Operating in FMS mode
With the software option "Encoder/Decoder" Major BOS 2a2 can be extended to a FMS control panel.
Possible FMS functions are the ID transmission at PTT keying and the transmission of up to two
arbitrary, programmed FMS telegrams (e.g. conversation request) using the two call buttons. in this
case, these are, of course, no longer available to transmit call 1 or call 2.
By conneting our FMS handset Commander 5 FMS to the D-Sub connector for external conversation
devices (handpiece or headset), the Major becomes ready for FMS use.
Here, the FMS handset can also be used as an alternative to the usual handpiece of the Major.
Therefor, the PTT output of the Commander 5 FMS must be configured to GND.

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Functions for TETRA digital radios (SW version 1.02 or higher)
For application in digital radio monitoring of the conversation request tone is necessary. As the Major
mutes its loudspeaker (LS) during transmission, this function has not been available if transmission
is conducted using the gooseneck (GN) microphone.
Thus, in version V1.02 and higher the LS can also stay active during a transmission with the GN
microphone. Circuits, on which no transmission takes place, are muted. Listening to active circuits
(current transmissions) is still possible during transmission. Here, the volume can be reduced.
This function can also be active if the LS would be muted because the handset is taken off.
For transmission using a different microphone (headset, handset or via external input) this option is
not available.
New registers:
270: Circuit 1
271: Circuit 2
272: Circuit 3
273: Circuit 4
Description for all 4 registers:
1st digit: 0 = if SH-PTT is keyed and handpiece is taken off, the LS status depends on
register 016/2
1 = if SH-PTT is keyed and handpiece is taken off, the LS is always active
4th-8th digit: max. volume for SH-PTT: 00000 (LS aus) to 32767 (max. volume)
Here, the listening volume for the circuit is set, the total volume depends on the
overall volume settings

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Potentiometers
Using the manual potentiometers located the volume of the different radio circuits can be set
individually. Furthermore, the overall volume of the Major can be controlled.
The functions can be extracted from the table below:
Poti Function / Volume Level
P1 RX-AF (Listening) Circuit 1
P2 RX-AF (Listening) Circuit 2
P3 RX-AF (Listening) Circuit 3
P4 RX-AF (Listening) Circuit 4
P5 AF of loudspeaker, (total)
Service Program
For Major BOS 2a2 the programming of the registers and the calibration of the electronic potentiometers
is accomplished using the service program. This program is accessible via the serial interface (for
pin assignment see section Cable Connection to PC). For this purpose a suitable terminal program
can be used: e.g. HyperTerminal (Windows), minicom (Linux).
The configuration of the serial interface is as follows:
data transfer rate 9600 bit/s
start bit 1
data bits 8
parity none
stop bit 1
flow control none
If the Major BOS 2a2 is switched on and the terminal program is started, the service program starts
after pressing ENTER ¬. showing the following menu:
Online - Monitor MBOS2a2
------------------------
Software: MBOS2a2
Version : V1.00
SW-Datum: 07.04.10
Option : Encoder/Decoder + AF-Squelch
Rxxx................read register xxx
Pxxx yyyyyyyy.......program register xxx with yyyyyyyy
A...................potentiometer calibration
Tx..................TX-output off/on (0/1)
Ixxxx...............switch on tone generator with xxxxHz (0000=off)
H...................detection of a headset
Q...................software reset
X...................exit monitor

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Registers of Major BOS 2a2
000 Radio circuit configuration 1
1st digit circuit 1 enabled, y = 1, n = 0
2nd digit circuit 2 enabled, y = 1, n = 0
3rd digit circuit 3 enabled, y = 1, n = 0
4th digit circuit 4 enabled, y = 1, n = 0
5th digit several active circuits possible y = 1, n = 0
6th digit on PTT if no circuit is active: use previous circuit = 0, error = 1
7th digit default "previous" circuit after power-on (binary sum of circuits = 0 - F)
001 Radio circuit configuration 2
1st digit circuit 1 enabled at power-on, j = 1, n = 0
2nd digit circuit 2 enabled at power-on, j = 1, n = 0
3rd digit circuit 3 enabled at power-on, j = 1, n = 0
4th digit circuit 4 enabled at power-on, j = 1, n = 0
5th digit circuits at power-on according to digits 1 - 4 = 0,
previously enabled circuits = 1
002 Squelch configuration 1
1st digit circuit 1
2nd digit circuit 2
3rd digit circuit 3
4th digit circuit 4
1st - 4th digit SQL active: AF = 2 (only with option AF-squelch)
high = 1
low = 0
003 Squelch configuration 2
1st digit circuit 1 AF is on: on squelch = 1, always = 0
2nd digit circuit 2 AF is on: on squelch = 1, always = 0
3rd digit circuit 3 AF is on: on squelch = 1, always = 0
4th digit circuit 4 AF is on: on squelch = 1, always = 0
004 Busy Out configuration
1st digit Busy Out circuit 1
2nd digit Busy Out circuit 2
3rd digit Busy Out circuit 3
4th digit Busy Out circuit 4
1st - 4th digit Busy Out Busy always off = 0
Busy active if TX is active = 1
Busy active if circuit is on = 2
005 Busy In LED configuration
1st digit Busy In circuit 1
2nd digit Busy In circuit 2
3rd digit Busy In circuit 3
4. digit Busy In circuit 4
1st - 4th digit Busy LED no function = 0
Busy active: TX-LED flashes = 1
Busy active: circuit-LED flashes = 2
Register Function

Register Function
006 Busy In, configuration of functions
1st digit Busy In circuit 1
2nd digit Busy In circuit 2
3rd digit Busy In circuit 3
4th digit Busy In circuit 4
1st - 4th Stelle Busy In no function = 0
active, mutes circuit = 1
active, disables PTT keying =2
active, disables PTT keying and mutes circuit = 3
active, disables circuit activation = 4
active, disables circuit activation and mutes circuit = 5
active, disables activation of any circuit = 6
active, disables activation of any circuit and mutes circuit = 7
007 TX In LED configuration
1st digit TX In circuit 1
2nd digit TX In circuit 2
3rd digit TX In circuit 3
4th digit TX In circuit 4
1st - 4th digit TX In no function = 0
active, TX-LED flashes = 1
008 TX In Funktionskonfiguration
1st digit TX In circuit 1
2nd digit TX In circuit 2
3rd digit TX In circuit 3
4th digit TX In circuit 4
1st - 4th digit TX In no function = 0
active, mutes circuit = 1
active, disables PTT keying = 2
active, disables PTT keying and mutes circuit = 3
009 Duplex configuration
1st digit TX In circuit 1
2nd digit TX In circuit 2
3rd digit TX In circuit 3
4th digit TX In circuit 4
1st - 4th digit simplex = 0
duplex = 1
010 AF input configuration of deactivated circuits
011 AF input configuration of activated circuits
1st digit circuit 1 to loudspeaker
2nd digit circuit 2 to loudspeaker
3rd digit circuit 3 to loudspeaker
4th digit circuit 4 to loudspeaker
5th digit circuit 1 to earpiece
6th digit circuit 2 to earpiece
7th digit circuit 3 to earpiece
8th digit circuit 4 to earpiece
1st - 8th digit circuit is muted = 0
listening volume = 1
maximum volume = 2 or 3

012 Tape relay configuration 1
1st digit relay on: at TX, y = 1, n = 0
2nd digit relay on: at every SQL, y = 1, n = 0
3rd digit relay on: at SQL on an activated circuit, y = 1, n = 0
013 Tape relay configuration 2
1st - 3rd digit overrun time of tape relay: nnn * 1 s (0 - 655 s)
012 AF input configuration of deactivated circuits
013 AF input configuration of activated circuits
5th digit circuit 1 to tape
6th digit circuit 2 to tape
7th digit circuit 3 to tape
8th digit circuit 4 to tape
5th - 8th digit circuit is muted = 0
listening volume = 1
maximum volume = 2 or 3
014 Headset configuration 1
1st digit microphone for red PTT-button
2nd digit microphone for external PTT-button
1st - 2nd digit gooseneck (GN) microphone = 0
headset (HS) microphone = 1
automatically switch to HS = 2
(no HS => GN microphone; headset present => HS microphone)
015 Headset configuration 2
1st digit threshold value for headset detection nnn (000 - 999) * 5 mV
if voltage is lower than threshold => headset is considered connected
016 Configuration of earpiece and loudspeaker
1st digit earpiece is off, if hung up = 0, earpiece is always on = 1
2nd digit loudspeaker is off, if earpiece taken off = 0, louspeaker is always on = 1
019 Functions of buttons CALL1, CALL2, PTT
1st digit function FMS ID code on PTT, y = 1, n = 0
2nd digit function CALL1-button
3rd digit function CALL2-button
2nd - 3rd digit no function = 0
CALL1/2 transmits as long as button is pushed = 1
send FMS 1/2 telegram = 2 (option Encoder/Decoder)
send tone sequence 1/2 = 3 (option Encoder/Decoder)
6th digit circuit(s) for CALL1-button, current = 0, binary sum of circuits = 1 - F
7th digit circuit(s) for CALL1-button, current = 0, binary sum of circuits = 1 - F
020 FMS telegram for PTT buttons
1st - 8th digit FMS ID-code (BLOOFFFF)
021 FMS telegram for CALL1 button
1st - 8th digit FMS 1 telegram (BLOOFFFF)
022 FMS telegram for CALL2 button
1st - 8th digit FMS 2 telegram (BLOOFFFF)
Register Function

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Register Function
023 Digits 9 and 10 in all of the 3 FMS telegrams
1st digit circuits where a FMS ID-code may be sent
(binary sum of circuits = 0 - F)
2nd - 3rd digit digits 9 and 10 for ID-code (register 020)
4th - 5th digit digits 9 and 10 for FMS 1 (register 021)
6th - 7th digit digits 9 and 10 for FMS 2 (register 022)
8th digit improved forerun and final bit 0 = 0
improved forerun and final bit 1 = 1
forerun according to standard procedure and final bit 0 = 2
forerun according to standard procedure and final bit 1 = 3
031 Tone sequence 1 for CALL1-button
032 Tone sequence 2 for CALL2-button
1st - 5th digit 5-tone sequence
041 Tone call decoder circuit 1
042 Tone call decoder circuit 2
043 Tone call decoder circuit 3
044 Tone call decoder circuit 4
1st digit decode tone calls: none = 0, call1 = 1, call 2 = 2, both calls = 3
2nd digit activation of circuit upon decoded call
no activation = 0
activate new circuit, if no TX and handset lies on Major = 1
activate new circuit, if no TX = 2
activate new circuit = 3
no activation of additional circuit = 4
activate additional circuit, if no TX and handset lies on Major = 5
activate additional circuit, if no TX = 6
activate additional circuit = 7
3rd digit SQL-LED does not flash, no ring tone = 0
SQL-LED does not flash, ring tone = 1
SQL-LED flashes, no ring tone = 2
SQL-LED flashes, ring tone = 3
051 1st - 3rd digit Time limit for transmission (nnn * 1 s)
055 Configuration of forerun / overrun
1st - 2nd digit nn * 10 ms forerun time before tone sequence / FMS
3rd - 4th digit nn * 10 ms overrun time after tone sequence / FMS
5th - 6th digit nn * 10 ms time of advance PTT keying without AF
(may be no larger than 1st - 2nd digit)
080 Reference for tone sequence decoder 1
1st - 3rd digit max. duration of 1st tone = nnn * 5 ms
4th - 5th digit min. duration for all tones = nn * 5 ms
081 Reference for tone sequence decoder 2
1st - 3rd digit max. tone duration beginning with 2nd tone = nnn * 5 ms
5th digit tone call system : ZVEI = 0
CCIR = 1
ZVEI2 = 2
EEA = 3
ZVEI3 = 4

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Register Function
082 Reference for tone sequence encoder
1st - 2nd digit duration of 1st tone = nn * 10 ms
3rd digit duration of other tones = n * 10 ms
4th - 5th digit pause between call and ID-code = nn * 10 ms
083 Reference for group call decoder circuit 1
084 Reference for group call decoder circuit 2
085 Reference for group call decoder circuit 3
086 Reference for group call decoder circuit 4
1st - 2nd digit min. tone duration for single tone decoder = nn * 100 ms
3rd - 4th digit max. tone duration for single tone decoder = nn * 100 ms
(00 = decode as soon as min. duration is reached)
5th - 6th digit min. tone duration for special tone decoder (Ruf 1 / 2) = nn * 100ms
7th - 8th digit max. tone duration for special tone decoder (Ruf 1 / 2) = nn * 100ms
(00 = decode as soon as min. duration is reached)
089 Tone recognition
4th - 8th digit min. level for tone recognition from circuit 1 - 4 (0 - 32768)
210 noise suppression (AF mute) circuit 1
211 noise suppression (AF mute) circuit 2
212 noise suppression (AF mute) circuit 3
213 noise suppression (AF mute) circuit 4
1st - 2nd digit threshold value for activation of AF mute = nn * 0.9 mV
3rd - 4th digit threshold value for deactivation of AF mute = nn * 0.9 mV
214 AF squelch configuration circuit 1
215 AF squelch configuration circuit 2
216 AF squelch configuration circuit 3
217 AF squelch configuration circuit 4
1st - 2nd digit nn * 5 ms above threshold value until SQL
3rd - 4th digit threshold value (AF present) = approx. nn * 1.8 mV
5th - 6th digit nn * 5 ms below threshold value until SQL is gone
7th - 8th digit threshold value (AF gone) = approx. nn * 1,8 mV
220 Output level radio AF -> LS
221 Output level poti test tone -> LS
222 Output level call -> LS
223 Output level ringtone -> LS
230 Output level radio AF -> earpiece / headset
231 Output level poti test tone -> earpiece / headset
232 Output level call -> earpiece / headset
233 Output level ringtone -> earpiece / headset
240 Output level radio AF -> tape
241 Output level poti test tone -> tape
242 Output level call -> tape
243 Output level ringtone -> tape
250 Output level radio AF -> radio
251 Output level poti test tone -> radio
252 Output level call -> radio
253 Output level ringtone -> radio
4th - 8th digit 00000 = off - 32768 = maximum

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260 Input level adjustment and min. volume for circuit 1
261 Input level adjustment and min. volume for circuit 2
262 Input level adjustment and min. volume for circuit 3
263 Input level adjustment and min. volume for circuit 4
1st - 3rd digit input level
-6,0 dB (000) ... 0dB (060) ... +19,5 dB (255)
4th - 8th digit min. volume level (00000 - 32768)
264 4th - 8th digit Min. overall volume level (00000 - 32768)
270 TETRA function for circuit 1
271 TETRA function for circuit 2
272 TETRA function for circuit 3
273 TETRA function for circuit 4
1st digit 0 = if SH-PTT is keyed and handpiece is taken off, the LS status depends on
register 016/2
1 = if SH-PTT is keyed and handpiece is taken off, the LS is always active
4th - 8th digit max. volume for SH-PTT: 00000 (LS aus) to 32767 (max. volume)
Here, the listening volume for the circuit is set, the total volume depends on
the overall volume settings
Register Function
Reset to Factory Defaults
Register 999 Factory defaults are programmed
Register 998 reset to factory defaults, including poti settings
Attention! Reset is carried out without further confirmation!

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Board Layout
The connection cable MBOS2Kx to junction box MBOS2AB1 or MBOS2AB6 is connected to sockets
ST1 and ST2.
Sockets ST1 + ST2 for Junction Box
Radio 1 Radio 3
ST2 Pin 10 AF-input ST1 Pin 2 AF-input
ST2 Pin 14 GND ST2 Pin 16 GND
ST2 Pin 7 AF-output ST2 Pin 3 AF-output
ST2 Pin 8 AF-output ST2 Pin 4 AF-output
ST1 Pin 13 squelch input ST1 Pin 15 squelch input
ST1 Pin 9 busy line ST1 Pin 11 busy line
ST1 Pin 8 PTT keying ST1 Pin 6 PTT keying
ST2 Pin1 3 +12V, external DC from radio ST2 Pin 11 +12V, external DC from radio
Radio 2 Radio 4
ST2 Pin 9 AF-input ST1 Pin 1 AF-input
ST1 Pin 4 GND ST2 Pin 15 GND
ST2 Pin 5 AF-output ST2 Pin 1 AF-output
ST2 Pin 6 AF-output ST2 Pin 2 AF-output
ST1 Pin 14 squelch input ST1 Pin 16 squelch input
ST1 Pin 10 busy line ST1 Pin 12 busy line
ST1 Pin 5 PTT keying ST1 Pin 7 PTT keying
ST1 Pin 3 +12V, external DC from radio ST2 Pin 12 +12V, external DC from radio
All GND-pins are connected on the main board and can thus be switched.
ST 3 ST 12 ST 11
ST 10
ST 4
ST 1 ST 2

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Assignment of further Sockets
Sockets ST1 + ST2 (16-pin plug connectors inside the control set) are connected to the junction box
MBOS2AB1 (socket ST1) or MBOS2AB6 (sockets ST1...ST6) using the connection cables MBOS2K1
(2m) or MBOS2K2 (6m).
a) With junction box MBOS2AB1 up to 4 radios (radio circuits) can be connected via terminal strips.
Connection in parallel to additional Major BOS 2a2 (or rather MBOS2AB1) can also be achieved
over these terminal strips, if necessary.
b) With junction box MBOS2AB6 up to 4 radios (radio circuits) can be connected via 9-pin D-Sub
connectors.
Connection in parallel to additional Major BOS 2a2 (max. 6) is carried out directly via the 32-pin sockets
ST1...ST6 using connection cables MBOS2K1 (2m) or MBOS2K2 (6m) as needed.
Socket ST12 for ext. headset or handset (25-pin D-Sub)
Pin 1 PTT for ext. AF (Pin 6), active low
Pin 2 AF input headset microphone (electret)
Pin 3 AF input GND for headset microphone
Pin 4 PTT for headset, active low
Pin 5 +battery output (+12VDC, e.g. for Commander 5 FMS, max. 300mA)
Pin 6 ext. AF input, ca. 500mV in countercurrent with GND, high-resistance
Pin 7 PTT keying indicator (PTT sum)
Pin 8/9 free (- not used -)
Pin 10/12 GND
Pin 13 +battery (input for supply voltage +12V/1A)
alternatively the MBOS2a2 can also be supplied via the junction box
Pin 14 AF-output (earpiece of headset)
Pin 15 GND (earpiece of headset)
Pin 16 GND for headset-PTT
Pin 17 free (- not used -)
Pin 18 GND, PTT for ext. AF
Pin 19-23 free (- not used -)
Pin 24 TXD RS232
Pin 25 RXD RS232
Pin 26 free (pin exists on the board only)
Socket ST10 for tape connection (Monitoring) (6-pin DIN)
Pin 1 switching contact relay
Pin 2 switching contact relay
Pin 3 AF output (tape, +)
Pin 4 AF output (tape, - )

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Socket ST3 --> display
Socket ST4 --> handpiece
Socket ST9 --> gooseneck microphone
Socket ST11 --> hook and loudspeaker
Pin 1 hook switch
Pin 2 GND
Pin 3 AF output loudspeaker
Pin 4 GND
Connection Cable to PC
25pin at MBOS2a2 9pin COM at PC
12 GND 5
24 TXD 2
25 RXD 3

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Jumpers (Junction Box MBOS2AB1)
The polarity of PTT keying can be configured separately for every radio using jumpers JP1 to JP4
(position "1" (as in the scheme below) = +batt; position "2" = GND).
Jumper Function Pos. 1 Pos. 2
JP1 PTT keying of circuit 1 to +Batt GND
JP2 PTT keying of circuit 2 to +Batt GND
JP3 PTT keying of circuit 3 to +Batt GND
JP4 PTT keying of circuit 4 to +Batt GND
Board Layout (Junction Box MBOS2AB1)
The connection cable MBOS2Kx for the control set (Major) is connected to socket ST1. The radios
FuG1 to FuG4 can be connected via terminal strips ST3 to ST6.
1
8
FuG 3
FuG 1
8
1
1
8
FuG 4
FuG 2
8
1
TR4
TR3
TR1
1JP4
1JP3
1
JP1
R13
R14
R15
R16
R12
R11
R9
R10
R2
R1
R6
R5
R3
R4
R7
+C4
+C3
+C1
1
ST5
1
ST6
1
ST4
D2 D1
D3
1
17 32
16
ST1
TR2
1
JP2
R8
+C2
1
ST3
D4

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Pin Assignment (Junction Box MBOS2AB1)
Sockets radio 1 (ST3) to radio 4 (ST6)
Pin 1 AF input (earpiece, live)
Pin 2 GND
Pin 3 AF output (microphone, live)
Pin 4 AF output (microphone, dead)
Pin 5 squelch input (carrier, active at +12V)
Pin 6 busy-line (do not connect to the radio!!!)
Pin 7 PTT keying output (PTT, open collector max. 100 mA)
Pin 8 voltage supply (+12V, ext. DC from radio))
Connectivity Scheme (with Junction Box MBOS2AB1)
Using the connection cable MBOS2Kx and the junction box MBOS2AB1 (available separately) up to
4 radios can be cannected to the Major BOS 2 via terminal strips. Furthermore, several control sets
(or rather junction boxes) can be connected in parallel.
MBOS2AB1
Major BOS 2
ST1 + ST2
MBOS2Kx
FuG 2 FuG 3 FuG 4FuG 1
MBOS2AB1
Major BOS 2
ST1 + ST2
MBOS2Kx
MBOS2AB1
Major BOS 2
ST1 + ST2
MBOS2Kx
BG1
BG2
BG3
.
.
.
etc.
.
.
.
etc.
Level of the Microphone
Major BOS 2a2 exhibits an output level of approx. 500 mV (at 200 ohm) for the direct connection to
the secondary microphone input (at the rear) of a FuG8/9. If the Major is to be connected at the control
panel of the FuG8/9 (BOS connector), AF has to be diminished to approx. 4mV (at 200 ohm).
This is achieved preferably by integration of a voltage divider (10 kohm / 180 ohm) into the BOS
connector. Alternatively, the voltage divider can as well be integrated into the junction box MBOS2AB1.
Therefor, the resistors R1, R5, R9, R13 (for circuits 1-4) must be changed from 0 ohm to 10 kohm
and 180 ohm resistors have to be used as R2, R6, R10 and R14 (for circuits 1-4).

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Jumpers (Junction Box MBOS2AB6)
By the use of several jumpers different configurations of the junction box MBOS2AB6 can be achieved
as needed. Most of these configurations were mentioned already during the preceding sections, if
they are generally relevant.
The following table describes the functions of the respective jumpers:
jumper function pos. 1 pos. 2
JP12+13 carrier display of circuit 1 is is active at +batt GND
JP22+23 carrier display of circuit 2 is is active at +batt GND
JP32+33 carrier display of circuit 3 is is active at +batt GND
JP42+43 carrier display of circuit 4 is is active at +batt GND
JP14+15 PTT keying of circuit 1 connects to +batt GND
JP24+25 PTT keying of circuit 2 connects to +batt GND
JP34+35 PTT keying of circuit 3 connects to +batt GND
JP44+45 PTT keying of circuit 4 connects to +batt GND
JP16 GND of circuit 1 is connected to overall GND yes no
JP26 GND of circuit 2 is connected to overall GND yes no
JP36 GND of circuit 3 is connected to overall GND yes no
JP46 GND of circuit 4 is connected to overall GND yes no
JP11 TX level (AF output) of circuit 1 is 500mV 4mV
JP21 TX level (AF output) of circuit 2 is 500mV 4mV
JP31 TX level (AF output) of circuit 3 is 500mV 4mV
JP41 TX level (AF output) of circuit 4 is 500mV 4mV
JPBusy11 control set 1 is connected to busy-line circuit 1 JA NEIN
. . .
. . .
. . .
JPBusyXY control set Y is connected to busy-line circuit X JA NEIN
. . .
. . .
. . .
JPBusy46 control set 6 is connected to busy-line circuit 4 JA NEIN