> However, in the 1950s, IBM developed card-to-card directly without
>> paper tape and "over AT&T lines". Modems were developed to take good
>> advtg of the available bandwidth (about 1200 baud). Undoubtedly the
>> equipment and implementation was developed in close cooperation with >> AT&T.
> This was the IBM "Card-to-card" transceiver. I don't know when they
> first came out, but the Army started implementing them in a nationwide
> network in September of 1956.
I saw one in operation between the GE Lynn Mass facility and somewhere else in 1960 or 61, in the same room as the 704.
I believe they used 4-wire leased lines, with data access arrangement
> boxes provided by Ma Bell. So the signals going into the big grey box
> next to the reader/punch were analogue. I don't recall what the
> transmission rate was, but they sent EBCDIC directly without any
> translation to a 5-channel code and no added headers.
No, it would NOT have been EBCDIC, which didn't emerge until System/360 around 1965. Try BCD or maybe some 2 out of 12 code.
Julian Thomas: ID=jt domain=jt-mj period net
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In the beautiful Finger Lakes Wine Country of New York State! Warpstock 2005: Hershey, Pa. October 6-9, 2005 -
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There are very few personal problems that cannot be solved by a suitable application of high explosives.