Hi all,

I am currently testing the limitations in capability and backwards compatibility of Marklin Digital kit.

Is there a way of achieving the control of functions f1-f4 when sending commands via a 6020 control unit connected to a PC via the 6051 interface? I am looking to test limitations of the Motorola I protocol and I am aware that the control 80 unit did not have buttons for the additional functions, which the 6021 did have.

My test would be the ability to control f1-f4 of a locomotive fitted with a fx decoder via the computer-operated setup above (6020 central station). I have seen documentation that seems to indicate that the protocol did make provisions for additional functions, albeit sent in a different format compared to Motorola II.

Thanks for any help/pointers!

Edited by user 01 March 2025 17:51:48(UTC)  | Reason: Not specified

6020 was designed to be used with the Control 80 (6035) which had the keyboard and speed control. That model was only capable of operating with the initial protocol for Maerklin Motorola.
The 6036 was an updated version of the 6035, known as the Control 80f because it allowed limited functions (F0 to F4).
The 6021 included a dip switch that allowed for selecting the initial or the upgraded protocol, which opened up more functions, including being able to access F8 through F8 if the locomotive supported that feature.
The problem with using the adjacent number for those functions was that all other controls did not work while the unit was set to this address.

Regards

Mike C

thanks for all the comments

I'm George by the way and just trying to make the most of old kit (including a VERY old mac mini) that would otherwise need to be recycled or scrapped. I was aware that what I was trying to achieve was going to be a challenge or even not possible (there are no dip switches on the 6020 to switch protocols), however:

1. I do have a seemingly working and stable connection to the 6020 and my older digital locomotives on the track via the 6051 interface and a mac running an old version of RocRail. I can switch direction but don't have absolute direction capability of course. So in theory I am not limited by the control 80/80f
2. I have been reading online the inner workings of the Motorola 1 protocol https://www.heise.de/ct/...ion/cm/buch/digit_2.html (in German, but Google translate has helped) and it does appear that the protocol allows for some extended function-specific encoding for f1-f4, although this may not be accurate - third table in sequence

Thanks again for all the responses

You need to ask Clapcott this question, as he has knowledge of the digital systems and the protocols that most of us do not have.

Cheers…

Mike

Thanks for all the replies - the reference to the 6023 is very helpful, and has led me to the following link:

https://student.cs.uwate...52/marklin/commands.html


It appears that:

1. The 6023 could address special functions but did not expose that to the physical controls on the device (this functionality could only be achieved via the built-in interface)
2. The central unit circuit should be identical to the 6020
3. the 6023 was released before the 6021 so is part of the first generation of Marklin Digital
4. It is not clear whether the loco decoders of the period or the ones that followed could decode special functions in that old format or whether dedicated function decoders where needed. There is only mention of HO Panorama and Dance cars

So in summary, I think I'm still on the fence as to whether what I'm trying to achieve is possible. I intend to repair a 39160 loco from the early 2000s and run some tests with with the running gear lights. I can share results if of interest

My glimmer of hope here is that according to the link above, the 6023 used speed step 15 as the direction change command - this is Motorola I format, as the 6021 encodes the direction alongside every speed step command

It doesn't matter which of the three control units you consider, the reverse pulse is generated the same way.

The only difference is that the extended Marklin Motorola format is generated entirely within a microprocessor, and uses invalid codes that are considered as errors by the original Motorola chips to encode the direction bit and additional functions. The 6020 uses a microprocessor to drive an original Motorola 14xxx series transmitter chip to generate the signal sent to the track, and this is why you can NEVER get a 6020 to generate the extended MM2 format codes.

I think this is the Panorama car that is being referred to in the link I shared previously (Marklin 4999):



It had a built-in decoder and seems to have had at least interior lights and a moving waiter. If this was launched prior to the 6021, then it might support the theory that the old Motorola format had *some* type of extended function capability.

I fully understand that the 6020 cannot generate MM2 commands and many thanks for all the info on the hardware

No, the MM1 protocol does not have capacity for any function other than F0.

To operate items such as the 4999 and 4998 digital cars a different method is used, that really operates in the address space used by accessories such as the k83. One bit of the transmission is used to signify if the message is for an accessory decoder for a point or a signal, and if the bit is in the opposite state then the message is for a digital wagon. Four functions are available in the "digital wagon" protocol, but NOT F0.

Items that use the "digital wagon" protocol, that I know of, are as follows: -
4999 Panorama Car
4998 Dance Car
2668 King Ludwig Train, digital version, coach set.
49960 Measurement Car

There may be others that I have forgotten, but from memory the 49960 measurement car was the last time this was used.