Jump to content

Transcode (character encoding)

Add links
From Wikipedia, the free encyclopedia
This is an old revision of this page, as edited by Arjayay (talk | contribs) at 14:22, 25 April 2021 (Duplicate word removed). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
For other uses, see Transcode (disambiguation).

Six-Bit Transcode, or Six-Bit Transmission Code, was, for a few years, one of the three character sets used by IBM for Binary Synchronous Communications. Transmission using 6-bit Transcode had higher throughput than transmission using 8-bit EBCDIC or ASCII, provided that the data to be transmitted used a limited set of 48 characters.

The IBM 2780 data transmission terminal was announced with Transcode support in 1967. Its successor, the IBM 3780 data communication terminal, announced in 1972, dropped Transcode support and added a "space compression" option.

Transcode is a six-bit character code. It relates to IBM's punched card code but, like EBCDIC, it is not BCD. Its 64 values consist of the 26 uppercase letters, 10 numbers, 11 symbols, space, and 16 control characters. Its 48 printable characters are ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 .'-/@#$%&*⌑; it cannot represent ,:;!?"()[]<>+^=_\`{}|~. Characters are transmitted with odd parity. The 2780 cannot use the 16 control characters as data characters in Transcode mode.[1]

Code table

Six-Bit Transcode
_0 _1 _2 _3 _4 _5 _6 _7 _8 _9 _A _B _C _D _E _F
0_ Template:Chset-color-ctrl|SOH
0001 		Template:Chset-color-letter|A
0041 		Template:Chset-color-letter|B
0042 		Template:Chset-color-letter|C
0043 		Template:Chset-color-letter|D
0044 		Template:Chset-color-letter|E
0045 		Template:Chset-color-letter|F
0046 		Template:Chset-color-letter|G
0047 		Template:Chset-color-letter|H
0048 		Template:Chset-color-letter|I
0049 		Template:Chset-color-ctrl|STX
0002 		Template:Chset-color-punct|.
002E 		Template:Chset-color-punct|⌑
2311 		Template:Chset-color-ctrl|BEL
0007 		Template:Chset-color-ctrl|SUB
001A 		Template:Chset-color-ctrl|ETB
0017
1_ Template:Chset-color-punct|&
0026 		Template:Chset-color-letter|J
004A 		Template:Chset-color-letter|K
004B 		Template:Chset-color-letter|L
004C 		Template:Chset-color-letter|M
004D 		Template:Chset-color-letter|N
004E 		Template:Chset-color-letter|O
004F 		Template:Chset-color-letter|P
0050 		Template:Chset-color-letter|Q
0051 		Template:Chset-color-letter|R
0052 		Template:Chset-color-misc|SP
0020 		Template:Chset-color-graph|$
0024 		Template:Chset-color-punct|*
002A 		Template:Chset-color-ctrl|ius/itb
001F 		Template:Chset-color-ctrl|EOT
0004 		Template:Chset-color-ctrl|DLE
0010
2_ Template:Chset-color-punct|-
002D 		Template:Chset-color-punct|/
002F 		Template:Chset-color-letter|S
0053 		Template:Chset-color-letter|T
0054 		Template:Chset-color-letter|U
0055 		Template:Chset-color-letter|V
0056 		Template:Chset-color-letter|W
0057 		Template:Chset-color-letter|X
0058 		Template:Chset-color-letter|Y
0059 		Template:Chset-color-letter|Z
005A 		Template:Chset-color-ctrl|ESC
001B 		Template:Chset-color-punct|'
0027 		Template:Chset-color-punct|%
0025 		Template:Chset-color-ctrl|ENQ
0005 		Template:Chset-color-ctrl|ETX
0003 		Template:Chset-color-ctrl|HT
0009
3_ Template:Chset-color-digit|0
0030 		Template:Chset-color-digit|1
0031 		Template:Chset-color-digit|2
0032 		Template:Chset-color-digit|3
0033 		Template:Chset-color-digit|4
0034 		Template:Chset-color-digit|5
0035 		Template:Chset-color-digit|6
0036 		Template:Chset-color-digit|7
0037 		Template:Chset-color-digit|8
0038 		Template:Chset-color-digit|9
0039 		Template:Chset-color-ctrl|SYN
0016 		Template:Chset-color-punct|#
0023 		Template:Chset-color-punct|@
0040 		Template:Chset-color-ctrl|NAK
0015 		Template:Chset-color-ctrl|EM
0019 		Template:Chset-color-ctrl|DEL
007F

  Letter   Number   Punctuation   Symbol   Other   Undefined (Characters are shown with their Unicode equivalents.)

Code table (from 2780 manual)

Character
 		 Punched card
code		 6-bit
transcode		 Hex 
SOH 12-9-1              P 00
A 12-1            5   01
B 12-2          4     02
C 12-3          4 5 P 03
D 12-4        3       04
E 12-5        3   5 P 05
F 12-6        3 4   P 06
G 12-7        3 4 5   07
H 12-8      2         08
I 12-9      2     5 P 09
STX 12-9-2      2   4   P 0A
. 12-8-3      2   4 5   0B
⌑ 12-8-4      2 3     P 0C
BEL 0-9-8-7      2 3   5   0D
Sub 9-8-7      2 3 4     0E
ETB 0-9-6      2 3 4 5 P 0F
& 12    1           10
J 11-1    1       5 P 11
K 11-2    1     4   P 12
L 11-3    1     4 5   13
M 11-4    1   3     P 14
N 11-5    1   3   5   15
O 11-6    1   3 4     16
P 11-7    1   3 4 5 P 17
Q 11-8    1 2       P 18
R 11-9    1 2     5   19
Space no punch    1 2   4     1A
$ 11-8-3    1 2   4 5 P 1B
* 11-8-4    1 2 3       1C
US 11-9-8-7    1 2 3   5 P 1D
EOT 9-7    1 2 3 4   P 1E
DLE 12-11-9-8-1    1 2 3 4 5   1F
- 11  0             20
/ 0-1  0         5 P 21
S 0-2  0       4   P 22
T 0-3  0       4 5   23
U 0-4  0     3     P 24
V 0-5  0     3   5   25
W 0-6  0     3 4     26
X 0-7  0     3 4 5 P 27
Y 0-8  0   2       P 28
Z 0-9  0   2     5   29
ESC 0-9-7  0   2   4     2A
' 0-8-3  0   2   4 5 P 2B
% 0-8-4  0   2 3       2C
ENQ 0-9-8-5  0   2 3   5 P 2D
ETX 12-9-3  0   2 3 4   P 2E
HT 12-9-5  0   2 3 4 5   2F
0 0  0 1         P 30
1 1  0 1       5   31
2 2  0 1     4     32
3 3  0 1     4 5 P 33
4 4  0 1   3       34
5 5  0 1   3   5 P 35
6 6  0 1   3 4   P 36
7 7  0 1   3 4 5   37
8 8  0 1 2         38
9 9  0 1 2     5 P 39
SYN 9-2  0 1 2   4   P 3A
# 8-3  0 1 2   4 5   3B
@ 8-4  0 1 2 3     P 3C
NAK 9-8-5  0 1 2 3   5   3D
EM 11-9-8-1  0 1 2 3 4     3E
DEL 12-9-7  0 1 2 3 4 5 P 3F

Devices using Transcode

References

  1. ^ {{cite book |last=IBM Corporation |title=Component Description: IBM 2780 Communications Terminal |year=1971 |url=http://www.bitsavers.org/pdf/ibm/2780/GA27-3005-3-2780_Data_Terminal_Description_Aug71.pdf |url-status=live |archive-url=https://web.archive.org/web/20200726231256/http://www.bitsavers.org/pdf/ibm/2780/GA27-3005-3-2780_Data_Terminal_Description_Aug71.pdf |archive-date=2020-07-26}
Retrieved from "https://en.wikipedia.org/w/index.php?title=Transcode_(character_encoding)&oldid=1019803073"