Browse Prior Art Database

AB AB/2/ EBCDIC Compatible Code

IP.com Disclosure Number: IPCOM000081894D
Original Publication Date: 1974-Aug-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Hutter, C: AUTHOR

Abstract

The termination of telephone network control signals to A, B tone code, has led to many schemes for utilization of those tone signals for numeric input to computing systems through the telephone network. The following code arrangement extends the numeric multifrequency code to the alpha-numeric EBCDIC standard, which is recognized as an input to many existing data processing devices.

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AB AB/2/ EBCDIC Compatible Code

The termination of telephone network control signals to A, B tone code, has led to many schemes for utilization of those tone signals for numeric input to computing systems through the telephone network. The following code arrangement extends the numeric multifrequency code to the alpha-numeric EBCDIC standard, which is recognized as an input to many existing data processing devices.

In this method of assignment of bit significance, the standard multifrequency telephone AB tone code is extended to an ABA'B' multifrequency code and is compatible with the standard EBCIDIC code. The translation of ABA'B' to EBCIDIC can be implemented in hardware logic. For ease of identification, ABA'B can also be designated AB/2/.

Fig. 1 (AB/2/EBCDIC Conversion) is a chart of the standard EBCDIC zone and digit assignments shown across the top and left side, respectively. The AB code consists of sixteen values providing for an exact match with EBCDIC. The chart identifies assignment of AB digits at the right-hand side and A'B' zones at the bottom. Thus an ABA'B' code of A1 B1 A'4 B'3 is equivalent to an EBCDIC value of C1 (i.e., 11000001) or an alphanumeric value of capital A. Similarly, an ABA'B' code of A1 B1 A'4 B'4 is equivalent to an EBCDIC value of F1 (i.e., 11110001) or an alphanumeric value of 1.

To provide receiver compatibility with both numeric and alphanumeric transmitters the sign-on procedure must contain a mode identifier. This enables the...