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REPRESENTATION OF INFORMATION IN MEMORY
Alphanumeric Data
Each DATANET-30 word can contain three six-bit alphanumeric characters. The 64 possible
bit combinations can be assigned to 64 symbols in any manner desired, because the DATANET-
30 does not use alphanumeric data as a unique code. Therefore, other system conditions will
determine the actual bit-pattern-to-symbol assignment.
An alphanumeric data word would look
like this in memory:
. . - - - - - - - - - - - - - - - - - - 1 s t Character
. . . . . - - - - - - - - - 2nd Character
3rd Character
18
13
12
7
6
1
Each DATANET-30 word can contain two eight-bit alphanumeric characters. The particular
code set used is dependent primarily on the remote terminals. This word might appear as
follows:
Spare
. - - - - - - - - - 1 s t Character
2nd Character
18
17
16
9
8
1
Eight-level teletype characters can be stored conveniently in memory as six-bit characters.
The DATANET-30 has two special instructions to facilitate stripping off and checking the parity
and control bits when a character is received, and generation and insertion of parity and control
bits when a character is to be transmitted.
If
desired for some applications, two eight-level
characters could be stored in a word as eight-bit characters including the parity and control bits.
18
- - - - - - - - - - - - - - - - - - - - - - 1st Character
13
12
. - - - - - - - - - - - 2nd Character
7
6
3rd Character
1 .
Three 8-level characters
stripped of control and
parity bits.
[ID&u&~~u CJ~@----,-------..--------
J-26
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