DCC address starting with a '0'?

[Suzie]

I noticed in one of DCC Concepts many helpful documents that they said 'please do not start your loco's DCC address with a leading zero.' No explanation was given but the suggestion was having a DCC loco address starting with '0' wasnt a good idea.

My loco DCC numbering protocol is for diesel numbers to drop the 3rd digit if the loco has a 5 digit number ie 57302 on the chip is 5702.

For kettles that have a 5 digit number ie 42020, is to drop the first digit and have a DCC address of 2020.

This caused a problem with Scotsman 60103. If I stick to my numbering protocol, I'd have to number it 0103 which means the address starts with the leading zero!

Technically, I cannot see a problem why a leading zero should cause a problem because the '0' is stored on the chip as part of a loco address without problem in the 2nd, 3rd and 4th address slots, so, why would the 1st be any different?

What's the esteemed panel's opinion, does a DCC address with a leading zero cause problems within the decoder and should it be avoided? Currently, Scotsman is actually addressed as 6003

103 is a short address and 0103 is a long address, they are not the same. Some command stations like NCE and Digitrax will allow you to use either address, whereas other command stations will only allow you to use one or the other, so it depends which system you have as to which address you should use.

[Bigmet]

103 is a short address and 0103 is a long address, they are not the same. Some command stations like NCE and Digitrax will allow you to use either address, whereas other command stations will only allow you to use one or the other, so it depends which system you have as to which address you should use.

When first evaluating what was available, now well over 20 years ago, I was baffled (and remain so) over what possible utility there was in having two address groups available, 'short' and 'long'. Why would you want that? Anyone using this feature able to explain why they like it and what benefits it confers?

[centenary]

103 is a short address and 0103 is a long address, they are not the same. Some command stations like NCE and Digitrax will allow you to use either address, whereas other command stations will only allow you to use one or the other, so it depends which system you have as to which address you should use.

When first evaluating what was available, now well over 20 years ago, I was baffled (and remain so) over what possible utility there was in having two address groups available, 'short' and 'long'. Why would you want that? Anyone using this feature able to explain why they like it and what benefits it confers?

Funny enough, while trying to find tutorials on Decoder Pro, I came across this one https://youtu.be/OcLPvYKw_A4?si=FFmrYm64IrQ_Gm6r

In it, the narrator mentions the long and short address. He says he sets both for all his locos ie long 4137, short 37. The idea being if he takes his loco to the club layout and someone else has the same long address 4137, he can still run his 4137 under the short address 37.

Seems logical but whether it works or not, I dont know.

[aleopardstail]

it should work, in theory can also give a single loco a "consist" address as well

in theory the short addresses are 0-127 and extended 0-10,239 and can be considered as such, however for practical reasons most systems use 0-127 as short and 128-9999 as extended, if you enter an address to drive in the 0-127 range it will be considered a short address.

I think you need quite a capable system to always use the higher ones. I think Decoder Pro follows this

and the cap at 9999 is basically to allow displays to limit to four digits

the DCC packet that goes to the track has either a single byte or two byte address payload. the way this works is quite clever

the first byte is as usual 8 bits, the highest bit for 0-127 is zero, if the highest and next highest are "1" & "1" and what follows is not "111111" then a second byte follows, that gives 14 bits for the extended address range.

thus the system can "see" extended addresses of 0-127 as well as short addresses of 0-127 and see they are different.

note its only old stuff now that can only see and send the short address

you still have the issue though that on a display "63" as an 8bit value and "63" as a 14 bit value are the same number unless you always show four digits for extended addresses, and then it gets complicated.

it can be done, problem is a decoder that had both addresses programmed it needs to know which to use. for the Zimo MX600 I use this is bit 5 of CV #29, both addresses can be set, but the decoder only responds to one of them

[Bigmet]

Aha, thanks both! (What with being congenitally unclubbable, the one practical application is of no use to me!)

[Suzie]

103 is a short address and 0103 is a long address, they are not the same. Some command stations like NCE and Digitrax will allow you to use either address, whereas other command stations will only allow you to use one or the other, so it depends which system you have as to which address you should use.

When first evaluating what was available, now well over 20 years ago, I was baffled (and remain so) over what possible utility there was in having two address groups available, 'short' and 'long'. Why would you want that? Anyone using this feature able to explain why they like it and what benefits it confers?

In the original DCC specification there were only short addresses 1-127 (short address 0 is reserved for running a DC loco if the command station has this feature). This was considered inadequate and the long address feature was added so command stations and decoders that supported long addresses could work with more than 127 DCC locos.

[Suzie]

Funny enough, while trying to find tutorials on Decoder Pro, I came across this one https://youtu.be/OcLPvYKw_A4?si=FFmrYm64IrQ_Gm6r

In it, the narrator mentions the long and short address. He says he sets both for all his locos ie long 4137, short 37. The idea being if he takes his loco to the club layout and someone else has the same long address 4137, he can still run his 4137 under the short address 37.

Seems logical but whether it works or not, I dont know.

You have to change CV29 in the decoder to switch between the two addresses, it will only respond to one or the other.

[Suzie]

...thus the system can "see" extended addresses of 0-127 as well as short addresses of 0-127 and see they are different.

note its only old stuff now that can only see and send the short address

All command stations will work with some short addresses, not necessarily all 127. Bachmann E-Z Command does 1-9, Lenz does 1-99, Digitrax, NCE, MRC/Gaugemaster and ZTC does 1-127 as an example.

[Bigmet]

...note its only old stuff now that can only see and send the short address...

I had to go looking at my 'DCC start up notes' to get a handle on 'old stuff', and there it was. A business meeting in Cologne in February 1997 meant that I got to see my longtime colleague Detlev (who was and remains a keen model railway enthusiast) and he showed me his favourite model shop. The proprieter was adamant that I needed to avoid all the short address only systems, move directly to GO! aka four digit, which the leading brands had adopted with product available. Given that it takes time to introduce conforming product we must be well past 27 years...