There are two types of Cyber-conversion, cyber-conversion as it was known by the Mondasian Cybermen and Upgrading as it was known by the Cybus Cybermen. In both cases a Cyber-conversion unit was used to implement the conversion.
Cybus Cyber Conversion Unit
A Cyber-conversion unit was created by John Lumic on a parallel Earth to Upgrade humans into Cybus Cybermen.
The main facility for conversions was Battersea Power Station in London. (DW: The Age of Steel)
Appearance
The Cyber-Conversion unit took the form of a large cuboid device into which the subject was placed.
It had four mechanical arms, mounted on a universal joint which was able to descend on the subject when a cyber-like head was lowered onto the subject. (DW: The Age of Steel)
The arms consisted of:
- Two circular saws.
- Several knife like blades.
- Syringe filled with green liquid
- A laser
Earth built Conversion System
An Earth constructed conversion unit was constructed by the Cybus Cybermen upon arriving in our universe, this was constructed from materials within Torchwood 1 and therefore not sucked into the void following the Cult of Skaro's arrival and defeat.
These systems included a vaguely ovid shaped gurney upon which the newly converted stood/lay, one of these devices was taken by Ianto Jones and moved with his girlfriend Lisa Hallett attached and partially converted. (DW: Doomsday, TW: Cyberwoman)
Mondasian Cybermen Cyber-Conversion Unit
Mondasian Cybermen typically conditioned their subjects before Cyber-converting them. The unit used for this was frequently a wall mounted unit which conditioned and added various systems to the individual who was being converted. However even despite the conditioning it was possibile for individuals to fight the conditioning and escape the Cybermen's hold. (DW: Attack of the Cybermen, BFBS: The Crystal of Cantus)