Hello,

Thinking about connecting ML to a home automation system (SPC = stored program control) I stumbled over the B&O MasterLink Gateway, which is indeed a simple solution. But before investing money for this I would like to get more information about the MasterLink bus itself. The only thing I knew at the moment is that it uses an asynchronous protocol with the data rate of 19200 baud. Is there a more detailed specification available or has someone more knowledge about it?


Kind regards,
Andy

I don't think it's ever been published, so it would be reverse engineering time...

Datalink is more or less public, at least the frame structure, (although it is hard to get direct information from anyone as everybody seems to be trying to sell you something) and might have some similarities, but I wouldn't expect it to be too useful - ML probably needs much more complex communication.

I think the ML Gateway is the way to go. It is really expensive though, £1800.00 in the UK.

The ML Gatways costs 2010 € in Germany and there is not a lot of documentation about the functionality on the B&O website. Before spending this amount of money for a “simple” gateway I would like to get more information about it.

Attached is screen shot from a simple USB logic analyser. The data was taken from a 1611 converter when switching V. AUX on. Maybe it is possible to find patterns when taking a lot of data frames during the day ;-).

Any hints are welcome.

Lintronic has done something similar, it connected the lintronic box's IR connector to a pin of the 1611 converter and he is able to trigger actions based on commands passed on the ML.

But the MCL/Datalink protocol is older than the ML protocol, and I do not think you could get all the new Beo5 codes.

That said if you want to trigger only a few actions, like lights, the lintronic solution might be enough.

I am interested in the ML gateway myself, and it can do a lot, basically here is how it works:

When you set it up, you have a way to assign a unique number to all your B&O TV and Audio equipments.

Then you'll get a message every time one of these devices receive a command from the remote, but also if the state changes by itself... for example the DVD goes to the next track.

The Beo5 can be setup to send signals that are not recognized by the TV or Audio system, so they simply pass them through and you receive a message as well. So you can trigger an action in your home automation software.

If you do not have a Beo5, you can use LIGHT codes from the Beo4, they also pass through.

The ML gateway is 2 way, so your home automation system can send a signal to turn the TV on, change the volume, etc...

tournedos:

I don't think it's ever been published, so it would be reverse engineering time...

Datalink is more or less public, at least the frame structure, (although it is hard to get direct information from anyone as everybody seems to be trying to sell you something) and might have some similarities, but I wouldn't expect it to be too useful - ML probably needs much more complex communication.

hi,

i did a lot of research two years ago when i was planning out my b&o setup during the renovation. i found a white paper that describes how masterlink functions. it's probably still out there on the web somewhere. google may lead you to it...

scott

PhilLondon:

If you do not have a Beo5, you can use LIGHT codes from the Beo4, they also pass through.

As a first step that would be enough. Unfortunately the logic analyzer does not capture anything when pressing the LIGHT button followed by a number or something else on the Beo4. So it seems that these commands do not pass through (in my case through a BeoSound 3000). Is there a complete and detailed explanation of the ML Gateway features? From http://ikatu.com/en/rnd/mlgw it is possible to download an installation manual – but it is not very detailed.

BTW: From interpreting the data it seems that ML uses a standard RS232 communication protocol: 19200 baud, 8 data bits, one parity bit (which can be dropped), one stop bit. The last byte of a frame is always 00h the second last byte is a checksum (last 8 bits of the accumulation of all data bytes before).

Checksum generation (example applies to the above posted logic analyzer data):
C0h + C1h + 01h + 0Ah + 00h + 00h + 00h + 0Dh + 02h + 01h + 33h + 35h = 204h -> Checksum = 04h

Andreas:

Unfortunately the logic analyzer does not capture anything when pressing the LIGHT button

Try "LINK, LIGHT".

It may not be the Beosound 3000 that does not transfer the LIGHT command, but maybe it is the Beolink converter that filters it.

One thing you could test is a Beolink PC2 box. It has a USB port on one side. I do not know if it trasnfer all the ML codes to the computer or only some that are necessary.

P.

Attached is a schematic from a BV5. Nearly the same solution is used in BeoLink converter. The logic analyzer probe is connected to Pin 1 of the ML-ASIC, so it is possible to get the unfiltered packets from the MasterLink bus.

After work I try “LINK, LIGHT”.


Andy

All this info and testing is great!  Please keep this up guys.  I think there are many that are extremely interested but may not be technical enough to add much to the conversation. 

„LINK, LIGHT“ does not pass through too. I hope to get a ML Gateway compatibility list from B&O. Maybe the BS3000 needs a firmware update. Depending on the weekend weather I can check the behaviour with another audio and video source.

Andy

Instead of an update you will need a downgrade to a BS7000 I`m afraid. I had this setup some years ago with an AV9000, BS7000 in the mainroom and MX4000 and MCL2as in link rooms. Linked via Masterlink and converter boxes. LINK LIGHT commands were sent via ML without any problems, even timer controlled light sets from the BS7000. When I replaced the AV9000 with a BV7-40. The LINK LIGHT commands were still working, but not received by the BV7-40. When my BS700 and MX4000 were replaced by BS9000 / BV6-22 the LINK LIGHT commands didn`t work anymore.

If you have a BV7-40 MKIII or BS3 try to switch the ML Gateway function in the service menu to "on". Maybe that helps....(?)

Stefan

For a BeoLink Active or BeoLink Passive, the software version must be at least 1.6. Also, In order to enable ML Gateway on the Beolink Active or BeoLink Passive, you must enter the following buttons on the Beo 4:

/MENU/ /0/ /5/ /GO/

/STEP UP/

/GO/ 

What will MENU - 0 - 5 - GO - STEP UP - GO do? Will that enable BL active/passive to receive/send LIGHT- or LINK LIGHT commands?

If so, is there a similar procedure for a BV6, a BL 3500.....?

Stefan

You seem to know this ML Gateway quite well... I have got the following questions...

Which B&O products are compatible with the ML Gateway? And which aren't?

Do you know how the controller device connects to the ML Gateway over ethernet. Is it like a Telnet connection to a certain address/port.

Can several controllers connect to the same ML Gateway at the same time?

Thanks,

   Philippe

@ Stefan and beojeff: Thank you for the good information.

Unfortunately, I don’t have access to BV7-40 MKIII, BS3 BeoLink Active or Passive with firmware version 1.6. But, some minutes ago I was at my local dealer to ask for a firmware update of an old BeoLink Passive which has version 1.4. I hope this could be done. The technician will be back on Monday – hopefully with good news.

With a simple hardware I connected the MasterLink to a Windows PC via a standard serial interface (RS232) to capture ML messages. Attached is a screenshot of a little windows application (ML-Analyzer was a suitable name for it), which shows some messages. Now it would be a good time to have a detailed specification. Anyone?


Andy

Hi,

Some years ago i made a linux program that can control the PC2. It can control your basic MP3 collection and do some nice things with it. I reverce engineed the protocol until i had no time anymore..

Maby it will help you.

http://sourceforge.net/projects/kpc2/develop

Herwin Jan

Hello herwin,

Thank you very much for your contribution and joining the forum to post an answer. I believe your code could be very useful for reverse-engineering the MasterLink protocol. A fleeting glimpse at your code reveals that the information which comes via USB is not exactly the data which floats on the ML bus. So the BeoLink PC2 processor does some data shifting, packaging, etc.

Bye,
Andy

Thanks Herwin,

It is actually going to be very useful for me, for a different project I am doing with the Beolink PC 2.

I'd like to ask you 2 things...

Is your software emulating Beoport in Option 0,2,4 or 6?

How did you reverse engineer the protocol? Is there a software on the PC that would allow me to spy on the communication between the Beoplayer software and the Beolink PC 2 box over USB.

P.

By curiosity, how did you connect masterlink to your rs232 interface, could you share your setup ?

D.

Hi dgillier,

Here are the steps:
1.    Open a BeoLink Converter or another B&O device with MasterLink
2.    Find the MasterLink level shifter  - in case of the Converter 1611 it is a IC called ML-Asic)
3.    Connect the Rx line to a RS232 level shifter (e.g. MAX232)

The current setup lies on my desk and needs too much space for work. Therefore, in case I got enough information about the ML protocol, I want to prepare a small PCB with the ML- and RS232 level shifter on it, or a PCB with the ML level shifter and an USB Device (e.g. from FTDI).

Andy

PhilLondon:

Is your software emulating Beoport in Option 0,2,4 or 6?

I thought it was Option 6, but dunno for shure anymore...

PhilLondon:

How did you reverse engineer the protocol? Is there a software on the PC that would allow me to spy on the communication between the Beoplayer software and the Beolink PC 2 box over USB.

Yust use a USB sniffer on windows, you can google on it. It was pretty straidforward.

Herwin Jan

Here is a new screenshot of the ML-Analyzer. The BS3000 transmits date and time information via ML to synchronize other devices like link speakers (e.g. LCS9000/BL3500). I wonder if the Audio master would use this information as well. So it would be possible to synchronize all ML devices with a DCF77 clock. In the current setup it is only possible to read ML messages. So I can’t test this – I need more hardware ;-).
Furthermore the Audi master sends source status telegrams if the status changes for example due to a Beo command which changes the CD track or the radio channel.

Andy

A little off topic Andy, I must compliment on your avatar, as the very same image is my desktop background! I was waiting for it to show up on an avatar here sooner or later, good pic.

Thank you for the compliment Evan. I like this picture too and therefore used it for a mouse pad at home as well.