HAYES MICROCOMPUTER PRODUCTS, INC. FOR IMMEDIATE RELEASE P.O. BOX 105203 Atlanta, Georgia 30348 404/449-8791 Peggy Ballard/Sharon O'Brien HAYES ANNOUNCES ENHANCED SERIAL INTERFACE AND ENHANCED SERIAL PORT FOR COMMUNICATIONS MANAGEMENT ATLANTA, GA., October 30, 1989 - Hayes Microcomputer Products, Inc. today announced a public domain specification for an Enhanced Serial Interface (ESI). Also announced were Enhanced Serial Port (ESP) hardware products for the IBM Microchannel and IBM XT/AT or EISA bus computers. The ESI specification and supporting ESP hardware provide a cost-effective communication co-processor to manage the flow of data between an external high speed modem and personal computer system. This technology prevents loss of data resulting from buffer overflow errors and provides maximum data throughput for high speed modems. Use of software that supports extended memory or RAM disk, background communication programs, Terminate and Stay Resident (TSR) software, and local area network connections places increased workload and time constraints on personal computer systems. Software that supports extended memory under DOS and multitasking systems, including Microsoft Windows, OS/2, and UNIX, shares system resources, affecting the system's ability to handle real time interrupts generated by high speed serial communications. These programs and system software packages are being rapidly adopted by advanced business users. During the development of Hayes V-series ULTRA Smartmodem 9600 (ULTRA 96), the company recognized that system software trends and actual modem throughput of 38.4 Kbps require a system solution to ensure that buffer overflow errors do not cause characters to be lost and that high speed modem performance is maximized. The Enhanced Serial Interface (ESI) specification is an extension of the familiar COM card used in personal computers. ESI includes the definition of I/O, control registers, buffer control, Direct Memory Access (DMA) to the system, and interaction with attached modem devices. The ESI document describes the hardware level interface and is useful for software or hardware developers who wish to implement these functions. Hayes ESP for Microchannel and Hayes ESP for the XT/AT or EISA bus computers are two hardware products which provide a cost-effective communication co-processor function for the PC system. Both products support dual serial ports, each operating at speeds ranging from 300 bps to 38.4 Kbps. This co-processor manages a bi-directional 1K byte FIFO buffer for each channel. In addition, the co-processor implements automatic flow control between the system and the external modem as well as providing DMA transfer to the system's memory for optimum performance and reduced software overhead for data communication sessions. "No one wants to find out they are using high speed error-control modems and losing characters between the modem and the PC," said Hayes President Dennis C. Hayes. "We have provided this solution at a time when only the most advanced system users are beginning to recognize the need," he added. "Microsoft commends Hayes for making the Enhanced Serial Interface available to the industry as a public domain specification," said Steve Ballmer, Senior Vice President, Systems Division, Microsoft Corporation. "It improves communication performance and allows high bandwidth data transmission from OS/2 applications," he added. The ESI specification is available from Hayes Customer Service at no charge, and interested developers are encouraged to register with Hayes. In addition, limited quantities of Hayes ESP hardware will be available in first quarter 1990 for developers to test their software supporting ESI. Hayes ESP for Microchannel will have an estimated retail price of $349 in the U.S. and CN$499 in Canada. Hayes ESP for IBM XT/AT and EISA will have an estimated retail price of $299 in the U.S. and CN$399 in Canada. Both products will ship to Hayes North American, Asian, and European distribution networks in second quarter 1990. For more information about Hayes ESP and the Enhanced Serial Interface, contact Hayes Customer Service at 404/441-1617 (United States); 416/283-2627 (Canada); (852) 5-845-9818 (Hong Kong); or 01-848-1868 (United Kingdom). Best known as the leader in the microcomputer modem market, Hayes develops, supplies and supports computer communications equipment and software for personal computer and computer communications networks. The company distributes its products through an international network of authorized dealers, resellers, system integrators and original equipment manufacturers. # # # Feature Overview Hayes Enhanced Serial Port (ESP) HAYES ESP The Enhanced Serial Interface specification and supporting Enhanced Serial Port hardware provide a cost-effective communication co-processsor to manage the flow of data between an external high speed modem and personal computer system. This technology prevents loss of data resulting from buffer overflow errors and provides maximum data throughput for high speed modems. Operating Modes Normal Mode - Emulation of 16450 UART for transparent operating with existing DOS software applications - supports data rates to 115 Kbps - Transparent operations with OS/2 communications software using standard OS/2 device drivers - Selectable receive hardware flow control and 16 byte character buffer for 16550 UART emulation buffer Enhanced Mode - Hayes ESP is managed by a communications co-processor - Dual transmit and receive 1K buffers and flow control ensure bi-directional data integrity to 38.4 Kbps - Direct Memory Access (DMA) data transfers between the PC system and Hayes ESP maximize throughput to 38.4 Kbps by lowering the overhead of processor received data interrupts Port Control and Operations Normal Mode Character Buffering and Flow Control - 16 character receive FIFO buffer - RTS hardware flow control - DTR hardware flow control Enhanced Mode Character Buffering and Flow Control - 1K bi-directional FIFO buffer to service DMA block transfers - RTS/CTS hardware flow control - DTR/DSR hardware flow control - XON/XOFF software flow control - Transparent XON/XOFF software flow control Dual Port Operation - Hayes ESP provides two serial ports which can simultaneously manage and transfer data to 38.4 Kbps Bus Interface - Hayes ESP for the MCA bus - Hayes ESP for XT/AT or EISA bus Operating System Interface Normal Mode - Existing DOS applications - OS/2 communications software using standard OS/2 device drivers Enhanced Mode - In order to utilize the 1K byte FIFO buffer, flow control, and DMA features of Hayes ESP co-processor, software support of the Enhanced Serial Interface (ESI) is required - For MS DOS a device driver supporting ESI must be included as part of the controlling application - For multi-tasking environments such as Microsoft Windows, OS/2, and UNIX, a separate standalone driver is required to support applications written for these environments # # #