Browse Prior Art Database

Programmable Communications Adapter

IP.com Disclosure Number: IPCOM000081505D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 4 page(s) / 147K

Publishing Venue

IBM

Related People

Brandner, J: AUTHOR [+2]

Abstract

This communications adapter is attached to a computer system which includes a keyboard to permit a systems operator to enter data, and microprogram routines are responsive to the keyed and other stored data to configure the communications adapter. The communications adapter can be configured to operate in a multipoint line, a switched line, or a leased line point-to-point mode. It can also be configured to operate at half or full rate. It can be configured to operate with a standby line and can be configured to operate in answer-tone-mode. This arrangement enables the operator to configure the communications system without having to change or reconnect any wires, and eliminates the need of a highly trained technician to configure the system.

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Programmable Communications Adapter

This communications adapter is attached to a computer system which includes a keyboard to permit a systems operator to enter data, and microprogram routines are responsive to the keyed and other stored data to configure the communications adapter. The communications adapter can be configured to operate in a multipoint line, a switched line, or a leased line point- to-point mode. It can also be configured to operate at half or full rate. It can be configured to operate with a standby line and can be configured to operate in answer-tone-mode. This arrangement enables the operator to configure the communications system without having to change or reconnect any wires, and eliminates the need of a highly trained technician to configure the system.

Communications adapter 40, Fig. 1, is part of computer system 5 which includes storage (main and control storage) 10, central processing unit (CPU) 20, channel 25 and I/O devices such as keyboard 35 attached to channel 25 via keyboard attachment 30. Modem 50 connects to communications adapter 40 and interfaces with a data transmission line 55 which links with another modem
60. A terminal or computer system 70 can be attached to modem 60.

Computer system 5 is a stored program system where instructions are fetched and executed under micro (mu) program control. The computer system operator keys in via keyboard 35 the name of the program for the type of communications operation which is to take place, i.e., transmit or receive as represented by block 100 in Fig. 3. The operator then enters configuration defining data via keyboard 35 into storage 10, as indicated by block 101. A microcoded program routine is invoked and forms a function selection byte 90 illustrated in Fig. 2, by interaction between storage 10 and CPU 20 relative to the configuration defining data. This is represented by block 102, Fig. 3.

The function selection byte 90 is analyzed in CPU 20 by microcoded program routines. It is first analyzed with respect to bits 0 and 4 for full or half-rate selection and for designating use of a normal or standby line. This analysis is represented by block 110, Fig. 3 and the actions performed are set forth in greater detail in Fig. 4a.

A Start I/O (SIO) instruction causes the microcode to retrieve the function selection byte 90 from storage 10. The microcode causes bits 0 and 4 in the function byte 90 to be tested. If bit 0 is a one, then bit 3 in a CPU register (LSR) is set to a one. Otherwise its state is unchanged. If bit 4 is a one, then bit 2 in the same CPU register (LSR) is set to a one. Additionally, the microcode sets bit 1 in the CPU register (LSR) to a one, which will function to indicate that the data terminal is ready after the contents of the CPU register (LSR) have been transferred to a control out register 41 in communications adapter 40, in response to an I/O Control Load instruction. The foregoing sequence of actions are represented by bloc...