The First Speech Synthesizer by HP: Revolutionizing Computer Technology
Table of Contents
- Introduction
- Background
- The First Speech Synthesizer by Hewlett Packard
- Lack of Documentation
- Reverse Engineering the Protocol
- Tracing the Hardware Connections
- Building an Interface Board
- Interfacing with the Speech Module
- Initializing the Vocabulary
- Generating Speech
- Adjusting Pitch
- Querying the Status
- Identifying the Module
- Understanding the Command Format
- Conclusion
The First Speech Synthesizer by Hewlett Packard
In the world of vintage computing, finding rare and unusual peripherals can be both exciting and frustrating. One such device is the first speech synthesizer ever made by a major manufacturer. And this particular speech synthesizer, as the web page claims, was manufactured by none other than Hewlett Packard (HP). Unlike the speech synthesizers for small personal computers, this HP speech synthesizer was specifically designed for their mini computers, such as the HP 1000 or 3000 series. Despite its intriguing nature, there is a dearth of documentation available for this particular device, leaving enthusiasts to rely on their own resourcefulness and ingenuity.
Background
Before diving into the details, it's important to set the stage and provide some Context. The speech synthesizer in question is a vintage piece of technology, dating back to a time when computer peripherals were not as commonplace as they are today. This HP speech synthesizer was likely put into service in the mid-1980s, as indicated by the stamps on the device itself. However, exact dates and usage details are scarce.
Lack of Documentation
One of the biggest challenges in working with this HP speech synthesizer is the lack of documentation. Unlike modern peripherals with comprehensive manuals and protocol guides, the only available documentation for this device is a mere page and a half article in an old HP journal. No instruction manual, protocol manual, Pin-out Diagram, or schematic is available. The only exception is some old software called the Voice Exerciser, which is in compiled binary format rather than source code. Additionally, the lack of information about the software and hardware setup for the HP 1000 series mini computers further complicates the situation.
Reverse Engineering the Protocol
Faced with the absence of documentation, one potential avenue to explore is reverse engineering the protocol used by the speech synthesizer. As a starting point, the article found in the HP journal provides some Insight into the protocol's basic structure. It mentions an escape sequence that begins with "Escape Ampersand Y S" and ends with "Escape Ampersand Y U". Unfortunately, the article lacks in-depth details about the formatting of the commands and the data itself.
Tracing the Hardware Connections
To gain a deeper understanding of the speech synthesizer's inner workings, an examination of its hardware connections is necessary. Opening up the device reveals several key components. At the heart of the synthesizer is a Z8 microprocessor with a piggybacked ROM. This ROM contains the firmware responsible for generating speech. The device also features RAM chips, a speech processor (TMS5220), an audio amplifier, and various RS-232 line drivers and receivers. Nevertheless, determining the specific functions and connections of these components requires further investigation.
Building an Interface Board
In order to interface with the speech synthesizer and experiment with its capabilities, a custom interface board is necessary. The goal of this board is to establish communication between the synthesizer and a modern computer or microcontroller. To achieve this, a DB15 connector is used to connect to the speech module, while a DB25 connector interfaces with the host computer's serial port. Additionally, the board includes a DC-DC converter to provide the required power voltages for the speech module.
Interfacing with the Speech Module
With the interface board in place, the next step is to establish communication with the speech module. Despite the limited knowledge about the protocol and command formatting, it is possible to develop a Python program that sends commands to the module. Using trial and error, various commands can be tested to Elicit different speech outputs from the module. Through this iterative process, the specifics of the commands and their effects can be deduced.
Initializing the Vocabulary
One crucial aspect of working with the speech module is initializing its vocabulary. The module has a limited capacity for storing words, requiring a careful selection process. By preparing a list of words and their corresponding definitions, the vocabulary can be initialized on the module. This initialization process involves sending each word's definition as a command to the module, effectively populating its memory with the desired vocabulary.
Generating Speech
With the vocabulary initialized, the speech module is ready to generate speech. By constructing the appropriate command sequences, consisting of escape codes and word identifiers, the module can be instructed to speak specific phrases. Through the Python program, users can input desired phrases and witness the module transforming text into audible speech.
Adjusting Pitch
One interesting parameter of the speech module is the ability to adjust the pitch of the synthesized speech. By manipulating the pitch setting in the command sequences, the module can produce speech with varying pitch levels. This feature adds versatility and allows for more expressive speech outputs.
Querying the Status
To gain insights into the module's operations, it is essential to query its status. This can be done by sending specific commands that prompt the module to provide information about its internal state. By analyzing the responses received from the module, details such as the availability of speech buffer space and other operational metrics can be determined.
Identifying the Module
In order to establish its identity, the module can be queried to provide information about its model. This can be achieved by sending a particular command that instructs the module to respond with its model number. By receiving this identification response, users can confirm the specific model of the speech module.
Understanding the Command Format
Dissecting the command format used to communicate with the speech module is critical for developing a comprehensive understanding of its capabilities. By examining the disassembled source code obtained from the ROM, the structure and composition of the command sequences can be deciphered. This knowledge enables users to exert finer control over the speech module and explore its full range of functionalities.
Conclusion
Working with the first major manufacturer speech synthesizer by Hewlett Packard presents both excitement and challenges. The lack of documentation necessitates a combination of reverse engineering, hardware exploration, and software experimentation. Through careful analysis and creative problem-solving, enthusiasts can uncover the secrets of this vintage speech module and breathe life into its unique capabilities. By understanding the command format and employing a custom interface board, users can generate speech, adjust pitch, query status, and explore the frontiers of speech synthesis in the early computing era.