Bar Codes on DCA Letters

[postggj]

may i ask what dots you are reading

 

i hope its not the florescent ones

 

they are not used any more

[banker_rhymes_with]

Hello Postggj!

 

i hope its not the florescent ones

 

they are not used any more

 

Sorry, could you explain that?

 

Thanks.

 

Cheers,

BRW

[postggj]

the blue florescent dots were used when we manual coded each letter

 

we sat behind a keyboard, pre IT revolution and typed the postcode which then was stamped onto the letter

 

that letter then went to another machine that read the dots

 

its called an ocr

 

optical character recognition

 

that machine short coded it to the nearest mail centre for that code

 

ocr is still used but a machine called an imp does the work i used to do on the keyboard

 

its by two sets of barcodes

 

one line to the nearest mail centre

 

the second sorts it into walks at that mail centre to go to the local delivery office

[hybrid77]

may i ask what dots you are reading

 

i hope its not the florescent ones

 

they are not used any more

 

I've received a letter today with them on??

 

Edited June 11, 2010 by hybrid77
added image

[postggj]

?????????

 

Any Chance Of Posting Up The Envelope Onto Your Thread

 

Google Photobucket To Post

[banker_rhymes_with]

Hello Postggj!

 

Thanks, I thought you meant the Orange ones, that clears that up.

 

It's the Orange ones we need to crack, but as far as I can now tell, there is no date in them.

 

The upper Track Code contains a day of the month, location of machine that printed the Barcode, a time stamp, and so on. That gets encrypted and creates the upper Barcode. IOW, it cannot be read by eye and there is no Character Mapping published.

 

The lower Route Code contains the Postcode and delivery point details and that is also encrypted, so that cannot be read by eye either.

 

The secret to cracking them will be to establish the encryption, and then gradually work out which elements of the cracked code say what.

 

i.e. the upper one may start off as:

 

Machine = 154

 

Time = 07:46

 

Day of Month = 17

 

Serial of item = 12566578954

 

So could end up as:

 

15407461712566578954

 

That then gets encrypted into, say:

 

2154161765151586

 

That then gets turned into a Postal Barcode, which needs, say, four Bars per character, so needs 64 lines.

 

So, firstly we have to work out the algorithm that turns this:

 

2154161765151586

 

Into this:

 

15407461712566578954

 

Then we have to work out which bit is what, i.e.

 

154-0746-17-12566578954

 

The main bits of interest would be the 154, the time of 07:46 and the 17 for the 17th day of the Month.

 

The Lower Barcode is also of interest, because that proves where the Envelope was sent, so proves it was sent to the same Address as the DN was sent to.

 

Whilst it is not a Date in full, if the DN was dated, say, the 16th and the Barcode confirms the Envelope was Barcoded by Royal Mail on the 17th at 0746 in the morning, and the lower Barcode confirms the Postcode...and the Envelope was 2nd Class or UKMail etc, then on any Balance of Probabilities, any sane Judge will agree the DN was posted in that 2nd Class Envelope, and sent to your Address etc.

 

I hope this makes some sense.

 

Cheers,

BRW

Edited June 11, 2010 by banker_rhymes_with
Typo

[barracad]

the blue florescent dots were used when we manual coded each letter

 

we sat behind a keyboard, pre IT revolution and typed the postcode which then was stamped onto the letter

 

that letter then went to another machine that read the dots

 

its called an ocr

 

optical character recognition

 

that machine short coded it to the nearest mail centre for that code

 

ocr is still used but a machine called an imp does the work i used to do on the keyboard

 

its by two sets of barcodes

 

one line to the nearest mail centre

 

the second sorts it into walks at that mail centre to go to the local delivery office

 

If you read the earlier posts you will see that what is being referred to is the barcode which is printed on the items nowadays, not the blue phosphor dots which were withdrawn in 1995 - clearly they would not be being printed on items 15 years later.

 

For your information, OCR is where the machine reads the actual address, not a barcode or dots or anything else for that matter - OCR refers to reading printed or handwritten text.

[postggj]

I Have It On Good Authority The Other Postal Operators Keep Hold Of The Mail Till The End Of The Week Before Its Passed Onto Royal Mail

 

Thats Why You Get Dca Letters On A Saturday

 

From Personal Experience In My Past A Letter From A Dca Can Take Up To Six Days To Be Delivered

[postggj]

If you read the earlier posts you will see that what is being referred to is the barcode which is printed on the items nowadays, not the blue phosphor dots which were withdrawn in 1995 - clearly they would not be being printed on items 15 years later.

 

For your information, OCR is where the machine reads the actual address, not a barcode or dots or anything else for that matter - OCR refers to reading printed or handwritten text.

 

THATS WHY ITS CALLED

 

optical character recognition

 

and i did say the blue florescent dots were not used anymore

[hybrid77]

From the information request DiddyDicky posted, these codes aren't encrypted, it *should* just be a case of decoding them. It's about 15 years since I did coding theory at uni, but as long as there's no encryption involved, it just needs a LOT of envelopes to work out the reverse character mapping. Work out the character set first so that each 4 bar group gets a code, then decode those codes into letters and / or numbers (the hard bit).

The 3 bit checksum is harder to work out, but it's basically just 3 additional characters on the end that confirm the rest of the line has been written correctly.

The reed-solomon part is kind of like an automatic spell checker

[Hoose]

you could always look at Calculate UK Postal Barcode Checksum

 

it might help

 

there arent any dates or times in the code