170 DEAR HACKER

170 DEAR HACKER

in some memory hole in the bowels of C&P. Am I right? If so, don’t tell everybody! If the authorities realize this we’re screwed.

I also have a question. My home answering machine is the hackable kind that recognizes tones. Something weird, though: at my office we use a phone system with AT&T HFAI-10 phones, and I can’t retrieve my messages directly using these phones. It’s as if the tones aren’t recognized. But if I take another nearby extension, and press the but- tons so that the tones on phone #2 come out the earpiece and into the mouthpiece of #1, they’re recognized. What would cause this? I know we have standard tones because I can use them for most voicemail applications. I’ve tried (my bank account, etc.). Any comments?

BK Bethesda, MD

As there are still relatively few areas of the country that have Caller ID up and running, we cannot give you a definite answer. But you should not be able to call

a blocked number under any circumstance. That seems pretty logical. If you find that you can, please tell us. The authorities are liable to realize this if it’s true—they don’t need us to tell them. Regarding your touch tone problems: you probably just have lousy sounding tones. Either they’re not loud enough on one particular instru- ment or they’re not long enough. This is a common problem with the newer phone systems. Get a tone dialer (white box) to overcome this no matter where you are. (It’s always sad to see technology marching backward.)

Dear 2600: One of the great values of your mag is that the back issues I have

saved are always full of things I didn’t understand a year ago but are invaluable now.

Case in point: your article on UNIX was mostly irrelevant to me in the winter of 1989, but a newly acquired Internet account makes it now altogether essential.

CH New York

TECHNOLOGY

We’ve always put out the magazine so it doesn’t become outdated. While operat- ing systems may change, the basic frameworks will remain intact. And the spirit of hacking links it all together.

Dear 2600:

A friend recently passed along a copy of your Autumn 1991 issue. I particularly liked the discussion about the postal system, but there are a couple of recent developments that I think merit some follow-up investigation.

Over the last year, the USPS has been installing new sorting machines that can read barcodes placed in the address block, rather than only in the lower right corner. (The USPS refers to this as “wide-area” barcod- ing.) Some of the questions raised by this new system are:

If the barcode is placed in the address block, does the letter get sorted by the BCS or the MLOCR?

Does it make any difference in sorting whether the barcode is placed above or below the address or in the traditional lower-right-corner location?

If a letter is barcoded with only a five-digit ZIP Code, does it get fed to the MLOCR to attempt to find the ZIP+4? If so, is there an advantage in using the address block barcoding so that the MLOCR’s nine-digit barcode doesn’t overlap the earlier five digit?

Further, quite recently the USPS has announced that it is using ZIP+6 coding. For street addresses, apparently the additional two digits are the last two digits of the house number. (For example, 1234 Main Street, Fooville, USA 12345-6789 will now be ZIP+6 encoded as 12345-6789-

34, with the check digit adjusted accordingly.) The additional two digits will show only in the barcode, not in the printed address.