Heidenhain Endat 2.2/01 or Endat 2.2/22
This question comes up quite a bit about the Heidenhain Endat . Saying Endat 2.2 is only half the story. There is Endat 2.2/01 which is the analog version. Endat 2.2/22 is the fully digital version. Endat 2.2/01 and Endat 2.2/22 are fully backward compatible with Endat 2.1. Endat 2.1 has not been used in DDR or Cartridge for about 6 or 7 years. All of AKM is also Endat 2.2 except for the LA and LB feedback models. LA and LB are inductive Endat encoders and these are still Endat 2.1.
The attachment explains the difference between Endat 2.1 and Endat 2.2.