[GreenKeys] Associated Press Special Dataspeed Receivers

[Jim Haynes]

Type 4 Dataspeed didn't get into production until I had left the company
in 1966, and I remember they were working on it back about 1958.  So I
never saw it in the field, but it looked like a fiasco in the making.

The sender wasn't all that bad, with backing up the tape to re-read,
but the receiver seemed to me to illustrate why Teletype needed to have
a technology of small core or disc buffer memories.  Aside from the
complexity of backing up and punching rubouts into the tape, the
people who are reading that tape don't want to waste all that time
reading blocks of rubouts.  And some customers want to transmit pure
binary data, where the rubout character is just as legal as any other.

The thing you talk about, where the circuit is interrupted briefly and
the system rubs out and restarts, isn't all that bad.  What's bad is
when the circuit gets noisy and you start getting lots and lots of
bad blocks to the extent that the tape is mostly rubouts.




jhhaynes at earthlink dot net