Digital Voice Prompts

The G1SLE WAV storage and playback unit is a self contained PCB roughly 90 x 65mm. The beacon texts are user programmable over the RS232 serial port using the X-modem protocol. The audio output is AC coupled and up to 4v p-p is available.

WAV files should be mono, 8bit, 8khz format.

Sufficient flash memory is provided to store up to 16 files of up to 512kbyte (64 seconds) in length. The flash memory is rated for up to 100,000 write/erase cycles and will retain data typically for 20 years.

When used with the Mk2+ repeater controller the playback unit accepts commands from the repeater controllers serial port.

As with most of my recent designs many of the components are surface mounted types. All resistors and capacitors are in 1206 or 0805 surface mount packages, with the exception of the 2 x SIL resistor networks. As through hole mounted components begin to become less available than surface mounted equivalents I have used surface mount packages for a number of ICs. These are mostly the larger SOIC DIL types which are reasonably easy to manipulate and solder with standard hand tools. The 89C51ED2 is in the common PLCC44 package, however since this part is fitted in a PLCC44 socket which is itself through hole mounted the constructor has no need to solder to the device.

By using the 89C51ED2, a powerful derivative of the long established 8051, the component count is kept very low, resulting in a compact simple design, capable of not only of playing back stored .WAV files but also, with separately available software, of generating PSK31 and RTTY.