Like with 7-level papertape codes also in 8-level papertape not all punches are data, also here error detection is coded. I know of the following ways:

Even parity, bit 8 is parity bit

Bit 8 is the "200" bit. It will not be shown in the following code displays. I know of two codes in this class:

Fieldata (Mobidic)


The Fieldata code. Curiously only the upper half of the code was defined, the lower half was intended for use for various control symbols. This lead to a large number of quite incompatible codes. Only the defined half is shown here.

ASCII (ISO, CCITT #5)


The ASCII standard. ASCII also standardized the tape format (8-level, even parity). There has been a huge discussion about which track should be the parity track, the fifth or the eight. Proponents of the fifth track thought that it would simplify equipment (the parity track would be the same regardless the tape level), however, sense won. This code has also been standardized by ISO and CCITT (see also the standards section). For CCITT it was the fifth coding, the fourth one was a 6-level code.

Even parity, bit 5 is parity bit

Bit 5 is the "020" bit. It will not be shown in the following code displays. Actually of course, any bit could be said to be the parity bit, but the coding makes it clear that bit 5 is the one added to the basic code. As far as I know only KDF (an old British computer) used this scheme. Actually, the codes used are barely 8-level, there are only two codes with the 8-th punch: space (octal 200, 240 with parity) and DELete (octal 337, 377 with parity). Also the legends lower case and upper case are clearly misnomers, but that is the way those symbols were on the keys. Only the first half of the code is shown in these tables:

KDF 9


The standard coding used.

KDF 9 Algol


This coding was used for Algol 60 programs.

Odd parity, bit 5 is parity bit

Bit 5 is the "020" bit. It will not be shown in the following code displays. Actually of course, any bit could be said to be the parity bit, but the coding makes it clear that bit 5 is the one added to the basic code. Also here most codes are barely 8-level, and in most cases only the lower half of the code is given with an explanation of the remainder. I know of the following codes in this class:

Honeywell


This code is clearly based on the standard 80 column punched card. Additional control symbols are added, and the NewLine is the only code with the 8-th bit punched (as the only punch).

EIA


This code is similar to the previous one, but the control symbols have been replaced by normal symbols.

IBM


One of the (probably many) tape codes from IBM. There are only a few codes with the high bit set: NewLine (200) and Peripheral Code 1 to 15 (201 to 217 with appropriate parity bit set). Again only the lower half is shown. The code clearly shows it's ancestry from the BCD card codes.

Bull


This is the only code in this section that can make some claim to the number of bits required. There are a few punctuation marks in the upper part and a few control marks. The curious positions of the letters and digits shows the relation with the Bull T8 Card Code. The extremely strange place of the letters I and O is explained there.

Exactly 4 bits

I know of only two 4 out of 8 codes, the code tables give incorrect entries hatched:

Telex (4 out of 8)


This is the 4 out of 8 code used in the US in Telex operations. I have no idea why the symbols are placed the way they are. It can clearly be seen that the code density is much less than with parity, there are only 70 code points. The lower case letters cannot be placed.

Anonymous 4 out of 8


I do not know the actual use of this 4 out of 8 code, but once I found it. When you combine the correct rows to a single row there appears some logic.