Scrounging parts from a desk phone

Scrounging parts from a desk phone

On uC Hobby, they took apart an old desk phone, scavenged it for parts, and wrote up what they found:

The easiest way I have found with modern technology to identify parts is to type all of the markings on the part into a Google search, and refine your search from there. If you then find numerous instances of the same repeated part of the markings such as, the 4 reed switches made by KUAN HIS. A search for KUAN HSI D2A050002 C35 results in no matches, but drop the C35 and you get 2 results. If you go the first link you find that the part number is D2A050002 and the manufacturer is KUAN HSI. Drop the Manufacturer and you can obtain more manufactures of the common part, and then if you weed through the results you should be able to find a data sheet for the item in question. You may have to omit some numbers to get rid of date codes, or manufacturer’s plant codes, the last digit or three. I never found a data sheet for a D2A050002, but I did find one for a D2A050000, at

Here’s some of what they got out of it:

  1. 42 capacitors from 1 microfarad to 220 microfarad
  2. 4 black 4 pin photo coupler anode cathode emitter collector
  3. 3 black 2 pin 682j inductors
  4. 2 102j 2 pin white inductors
  5. 4 8 pin reed switches D2A050002
  6. 4 ksp44 transistors epitaxial silicon transistors collector base 500v collector emitter 500v emitter base 6v
  7. 7 varied resistors
  8. 1 5.5v .47F Super capacitor useful as backup power for CMOS
  9. 1 121j – 120 uH inductor
  10. 5 varistors light blue flat discs brand _ _ _ varistor voltage – _ tolerance (k-10% l-15%,m -20%) – _ Type (disc or square) – _ _ element diameter
  11. 4 EPCOS tantalum chip capacitors
  12. 3 152j – 1.5 uH inductor
  13. many screws
  14. 2 transformers

Scrounging a Desk Phone

Discuss this article with the rest of the community on our Discord server!

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. His free weekly-ish maker tips newsletter can be found at

View more articles by Gareth Branwyn


Ready to dive into the realm of hands-on innovation? This collection serves as your passport to an exhilarating journey of cutting-edge tinkering and technological marvels, encompassing 15 indispensable books tailored for budding creators.