Today I stopped at a thrift and found a Blue/White metal device made by ISD and can't really figure it out. It has a place burn a chip and the one in it is ISD 1016 AP; a four inch speaker at the top and on the front side panel it has hook ups for a headset, in and audio, power supply. and RJ11 jack. On the circuit board I found this writing "ES001D Evaluction Unit 1995". There is no writing on the metal case or decals what so ever. Any one seen this unit before.