MICR madness

Have you ever looked at the bottom of a check? Ever noticed that string of characters in a weird blocky font? Well that's a MICR line. MICR stands for "Magnetic Ink Character Recognition" and is a technology hailing from the 50's. Its sort of interesting actually. At the time digital cameras were unheard of, CCD was probably at best glimmer in some researcher's eye. But banks wanted a way for computers to get information off check without human intervention. So MICR was developed.

MICR reads the signature of the magnetic ink and uses it to recognise characters of certain specially designed fonts. That part of the technology works beautifully. There numerals and a few special characters in the MICR fonts being deemed sufficient to encode the information on a check. However something smells in the world of MICR.

The standard format for a MICR line in the United States is too lax for my taste. There are two common formats for MICR lines personal checks (anything other then a number is a special MICR character translated to ASCII):

:111111111: 2222222< 3333 ;44444444444;

Field 1 would be the routing number which is the most tightly controlled of the fields. It is an ABA number, has a check-sum and is pretty reliably just like I typed. Field 2 is the account number, and three the check number. These two have all kinds of problems. Field four is an optional amount of the check. That is what most personal checks look like. Business checks generally take the form:

<3333< :11111111: 2222222< ;44444444;

With the field numbers being the same thing as in the personal check.

This is all well and good. If that was the whole story things would be easy. But things are rarely so easy. Many banks, especially community banks, printed their checks with just about any format of the above fields they could come up with. Now the routing number and amount are consistent (they were specified by the original spec) but the order of fields, what separators are used where, where there are spaces and everything else seemingly nearly random. So producing a parser that can understand even a small subset of the checks in circulation can be a pretty good task.

If you can't tell I've been fighting the things lately and am a little frustrated. There is still a good bit of time spent by tellers hand-keying check information because of this wonky bit of banking history. Too bad the ABA did not come up with a much more exact specification allowing easy interoperability between banks. Of course some of the checks I've seen do not even follow the layout that the MICR standard did create, so the problem would still exist. However that's life.