FDR's ISO8583 Specs Are Online

One of the best ways to familiarize yourself with ISO8583 as it is used in practice is to review a 'real world' specification as implemented by one of the payment systems industry's major players.  First Data (a.k.a. FDR or FDMS) posts their specs online.  You can sign up here:  http://www.fdms.com/specs - there's no checking or vetting that goes on.  First Data welcomes your interest.

[NOTE:  That FDR link only works with IE in my experience.]

These specs are good resources for a couple of reasons:

1. They're well-written.
2. They've been proven to work in production across a wide range of industries.
3. FDR does a good job keeping them up-to-date and relevant.

FDR being an acquisitive organization, there are specs for a number of different 'platforms' found there.  The list currently includes Atlanta, Nashville, North, Omaha, PayPoint and South.  Nashville, for example, is probably the old 'Concord/EFS' interface. 

Where to start?  We've implemented the host-to-host (a.k.a. 'leased-line') version of the 'North' interface.  It's a good one.  To find it, select North in the "Platform" drop-down and keep all other selections as "- All -".  In the match list that is compiled for you, you want document No. 4 - ISO 8583 Format Authorization Network Processing Specifications.  [NOTE:  Remember, this is a spec from First Data Merchant Services (FDMS), so the spec is all from an acquirer's viewpoint.]

Note that some times to get the complete picture, you'll need to augment the main spec with what FDR calls its 'QRGs' or Quick Reference Guides (see right-hand column of the match list).   Typically, these are industry-specific guides like Airline and Rental Car requirements that would otherwise clutter up the main document for the masses.   In this case though, there's one really important QRG you want to download: the one entitled North Authorization Guide ISO8583 Debit.  With more and more retailers pushing BIN lists to the POS with the goal of prompting or forcing debit, transaction mixes are moving inexorably away from credit and towards debit.  So, that 11-page QRG is quite a significant addendum.

For those of you using jPOS, please note that it's your responsibility as a developer to read these specs (or one like it) in their entirety on a field-by-field basis and then build the appropriate ISO Packager according to the guidelines laid down in the jPOS Programmers' Guide.