As part of building repeaters I built controllers and identifiers. The first Ider I built used a discrete diode array.
The circuit board had columns on the top side and rows on the bottom side. If memory severs me, the board's
capacity was about 120 elements. Since a zero has 19 elements, the board didn't hold much more than a call sign.
Newer technologies with increased size and simpler programming have far surpassed the old diode arrays.
Next generation Ider used Eproms. The Eprom Ider in my circuit box, was orginally tested using a manual
programmer. The programer consisted of two set of dip switches and a 555. The first bank of switches loaded
the address and the second set switches loaded the data. The chip was programmed by firing a 555 timer
which applied a write pulse. After testing my Eprom design using the manual programer, I quickly purchased an Eprom
programmer to ease message programming. All these designs were problematic, in that the message could
easily be miscoded. The next generation of Ider's the CW characters became fixed by the program. The numeric value
of a character could be repeated without concern of a missing dit. The PIC Chip design is documented below
(updated 4-21-2006)
Bob's Circuit & Program Box