GB2277854A

GB2277854A - Replaying speech from the parallel port of a personal computer

Info

Publication number: GB2277854A
Application number: GB9309139A
Authority: GB
Inventors: Martin David Risely
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-05-04
Filing date: 1993-05-04
Publication date: 1994-11-09
Also published as: GB9309139D0

Abstract

A self contained cartridge with connectors at each end allowing for the connection to the parallel port of a personal computer and to audio headphones. The cartridge allows for speech or music to be delivered to the wearer of the headphones under software control from the computer. Electrical power for the apparatus is derived from digital signals present at the computers parallel port. The cartridge includes a speech decoder IC1 and an operational amplifier with an adjustable potentiometer R3. <IMAGE>

Description

APPARATUS FOR REPLAYING SPEECH FROM THE PARALLEL PORT OF A PERSONAL COMPUTER This invention relates to apparatus for replaying speech from the parallel port of a personal computer of the type known as 'IBM Compatible'.

Personal computers of the type known as 'IBM Compatible' have never been able to generate human speech. Recently several devices have appeared that enable this facility, however these devices require to be installed inside a computer. Often this requires a confidence or technical knowledge beyond the average user.

According to the present invention there is a cartridge that plugs releasably into a port on the back of the computer. This port is known as the 'Parallel Port'. Speech is derived from digital signals present at the parallel port, converted to an electrical analogue of speech by the cartridge and presented to the user via headphones connecting to the cartridge.

Furthermore, electrical power required by the cartridge and headphones is also derived from digital signals present at the parallel port.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings.

Figure la shows the cartridge from the 'computer' end, figure ib from the 'headphones end' Figure 2 shows the cartridge in exploded view, thus the fixing and layout of the contents of the cartridge.

Figure 3a and 3b show a circuit diagram of the electronics Figure 4 shows the product as functional blocks TECHNICAL DESCRIPTION The power supply. Power is derived from digital signals present at the parallel port. In particular pins 2 and 3. The square waves at these pins connect to the apparatus via a mating connector of the type 25 way D type. The frequency is of the order of 20 KHz.

The duty cycle approximately 50%. Each square wave is rectified by diodes D1 and D2.

Capacitors C1 and C2 act as electrical reservoirs and also as low pass filters with the effective resistance of the diodes Dl and D2. The two rectified voltages are summed and input to the voltage regulator REGS. The output ofREG1 is +5V.

The speech decoder IC 1 on the printed circuit board connects electrically to the parallel port via the mating connector CN2 and in the way shown in figure 3b. The pins 2 to 9 carry digital data which when presented to the decoder is converted to an electrical analogue of speech. Inputs DO to D7 receive this digital data the analogue of which is output at AO/P. The computer is notified of the devices need for more data by the interrupt request line IRQ/. AO and Al are inputs under software control and are used to control the status of the device e.g. Encode or decode. CS/ is under software control also and is used to select or deselect the device. IC1 is clocked via a 1MHz quartz crystal as shown in fig 3b.

Pins 2 and 3 have dual functionality. In the first instance the data they carry is used by the speech codec. In the second instance the alternating pattern of these pins is used by the power supply as shown in figure 3a. Useage at a particular time is determined by the status of inputs AO and Al. These are under software control.

The analogue output is buffered by the operational amplifier IC 2. Attenuation is provided by means of R3. This is then output to headphones via the connector cNl OPERATION BY ThE USER The user will plug the device into any unused parallel port on his computer having first plugged headphones into the audio socket at the opposite end from the D connector: Speech is delivered to the user via the headphones under software control. The software is an essential part of the operation of the device but as it is not a part of this application is not described.

Claims

1. Apparatus for replaying speech from the parallel port of a personal computer.

Wherein a self contained cartridge with headphones is used for the reproduction of speech or music and no further apparatus or connecitions are necessary.

2. Apparatus for replaying speech from the parallel port of a personal computer.

Whereindigital signals present at the parallel port are converted to a speech analogue and drive headphones for use by the computer operator.

3. Apparatus for replaying speech from the parallel port of a personal computer.

Wherein electrical power necessary for the operation of the apparatus is derived from digital signals present at the parallel port ofthe computer.

4. Apparatus for replaying speech from the parallel port of a personal computer substantially as described herein with reference to figures 1 to 4 of the accompanying drawings.