Stentofon intercom systems after 1990 and still sold today .

Zenitel, Stento, Stentofon , Vingtor Marine AlphaCom  / ACM ( Stentofon AlpaCom inside )   

Stations with or without display . All VMP / Stentofon stations can be used.   Star wireing configuration - 4 wires separately to every station.

The ACM / AlphaCom is a smart choice when your VMP / MPC exchange has to be replaced . Standard  sizes: 138 , 80 and 36 (AlphaCom M) .

Earlier AMC boards used COM ports  to connect external systems.
Later AMC boards also have a RJ45 network connection, using IP addresses to access a network with external systems and functions.

The Stentofon AlphaCom / Vingtor Marine ACM ( AlphaCom inside ) was introduced  in the early nineties and these exchanges are still sold today .   They are compatible to the MPC / VMP system stations and wireing .  It's also easier to connect display stations  to the AlphaCom / ACM system  . Like the MPC / VMP exchanges with PMF / PMF-R proccesorboards,  the  AlphaPro / ACM exchange has an "userdata Backup / Restore" procedure , to make a backup on onboard eeprom(s) .

The most important notice!

Power OFF when plugging !

Like replacing boards in a computer ,  to avoid  serious damage on the exchange electronic boards   allways turn off  the power before replacing any board in the exchange !!

Circuit boards:

AMC-IP Module Control Board , from 2008 , The IP filterboard has RJ45 network connectors and  com ports.

AMC ver 9.12 Module Control Board , older systems + ACM-M without RJ45 network connector. 

AMC ver 01.04 Module Control Board , older systems  , software up to 7.xx

APC ver 01.xx Program & Clock Board , Master clock and 6 x program inputs

ASLT-2 Subscriber Line Board , Filterboards also for 6 x RJ45 connectors, easy to use on Cat5 network

ASLT Subscriber Line Board , Standard filterboards is connected to SUBCB

ASVP Stored Voice Message / Playback

APF Program Feed Board

AGA Audio Interface Board

Self service / fault finding on Stentofon AlphaCom and Zenitel Marine ACM ( AlphaCom inside ) .

Fans must work , check air inlets / air outlets.
PWR supply: All 4 Led's must be ON

Power OFF when plugging / unplugging any board inside the exchange.    If done with power ON:   the actual board is damaged beyond any repair + possible damage to other boards! 


Check exchange hardware status:

AMC Blinking Green light OK processor board

ASLT Steady Green light OK line board and stations / lines

ASLT Blinking Green light OK line board , check lines stations

ASVP Steady Green light OK Stored Voice Message / Playback Board

There is no LED on the Master Clock / Program Board


Five minutes after turning Power ON:   If one ore more of these indicators don't turn green, expect hardware failure inside the exchange.   

Picture is of a Stentofon AlphaCom 112 used in our workshop.


Programming and advanced fault finding / repairs :  Ask us, we have the knowhow  ( domestic / international service )


ACM-M series   is the smallest exchange.    1 x AMC-IP board + maximum 6 x ASLT boards 

How we connect subscriber lines to this exchange. 

Using  railmounted subscriber line connectors placed close to the exchange  and flexible wireing to the exchange  connectors.   

 Special   User spec.  16 channel optoinsulated remote output driver.  

Common problems :   Backup battery on the AMC board .

General programming preparation , what must be known before programming .

Sorting out what's inside the exchange : Version of running software on the Processor board, Stored Voice Message Playback Board, standard boards / extra function boards,  internal wireing schematic to local terminal numbers .

What's connected to the exchange : stations , stations catalog number , remote equipment and other hardware connected ,  ref. to terminal numbers inside  the exchange .


Programming : by using a pc with AlphaPro software . To make meaningful programming , repeated training and good system knowledge is a must .

AMC board service hints .   Easy service.    Changes in the programming .

Note!  It's a must to have a permanent backupfile available .  AMC backup battery lifetime often is found to be less than 10 years !


Check lines + stations status: Use a station with display to make this control . Read address and catalog number.

NOTE! 10 years service interval of user program  & backup circuitry. 

Have a backup ready before replacing the battery on the AMC board.

Backup to flash eeprom on the AMC board ( 28F010 ) = Dial from Super User : 7820 + M .

It's smart to make an extra backup on a new flash eeprom ( 28F010 ) = Dial from Super User : 7820 + M .

Measure the 3.6Volts backup battery  , in case of low battery voltage or old battery  it must be replaced .


Restore from backup = Dial from Super User : 7819 + M



Filterboards :

GND connection failure . Easy to fix.


Stentofon AlphaCom / Zenitel Marine ACM : extra function boards & related info.

PDB Power Distribution Board

MRBD Multi Relay Board w/Drivers

FBSAR Filter Board Speach Adapter Relay

MADER Microphone Amplifier for Dynamic & Electret microphone w/Relay

RIO Remote control I/O Controller + IIC Connection Board

PA 20W 20W power amplifier, from early 80's

PA 20W w / VOX 20W power amplifier w / VOX , from mid 90's

PA 30W InterGuard 30W power amplifier InterGuard , early 90's

PA 60W InterGuard 60W power amplifier InterGuard , from mid 90's


subscriber connection board w / RCO connector   SUBCB   

SUBCB subscriber connection board w / RCO connector NOTE!: RCO's uses positive logic, ( Off = 0VDC , ON = +5VDC )

 Non volatile multi message hardware  chipcorder

Download catalog from Zenitel

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