On 5/15/2014 5:52 PM, Micheal Butz wrote:
Yes but why these printable ebcdic codes
Six bits for a portion of the address leave two bits available. When the 3270 family was introduced, all printable characters had the x'40' bit on. The x'80' bit is set on or off to produce a printable character (see the 360 or 370 reference card for the then extant characters). Modern, extended data stream devices assign special meaning to the x'40' bit, but they also don't support ASCII any more.
For example, a bit value of 0A would first get x'40' ORed in, producing x'4A', which is printable. But a value of 16, turned into 56 is not, so x'80' is ORed to produce D6.
If your question is why use EBCDIC code, that may be due to early modems, that recognized a few line control characters, and expected printable characters for the data. Also the remote 3270 came in both an EBCDIC and ASCII variety, and ASCII support required printable characters for conversion (IBM 3272/3277 shows remote controls; even those were translated to ASCII printables).
Gerhard Postpischil Bradford, Vermont ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
