HEIDENHAIN PWM 20 - Manual (Page 25)

26 HEIDENHAIN ATS Software User's Manual
4.2 Absolute interfaces
 Encoders that have a 'C' or a 'Q' in their names use an absolute interface (EnDat or SSI).
There are EnDat encoders with and without incremental A/B sinusoidal signals.
The order designation indicates whether an encoder outputs incremental signals:
EnDat 21 without incremental signals
EnDat 22 without incremental signals
EnDat 01 with incremental signals A/B 1 Vpp
EnDat 02 with incremental signals A/B 1 Vpp
EnDat Hx with incremental signals HTL (as of 2014)
EnDat Tx with incremental signals TTL (as of 2014)
x designates: a = 2-fold interpolation
b = without interpolation
c = scanning signals x2
Also see "Interfaces of HEIDENHAIN Encoders“ brochure, ID 1078628-xx.