The NM-HDV based modules all use the c549 DSP chips. The quantity that are installed on the card depends on which bundle you buy.
NM-HDV-1E1-30 has 9 c549 DSPs (on 3 SIMMs)
NM-HDV-1E1-30E has 15 c549 DSPs (on 5 SIMMs)
NM-HDV-2E1-60 has 15 c549 DSPs (on 5 SIMMs)
1 c549 DSP in the HDV module can handle 4 simultaneous medium complexity calls (e.g. G.711 or G.729a codec) or 2 simultaneous high complexity calls (e.g. G.723.1 codec).
So with 9 DSPs that is 36 medium complexity calls (which is enough for one E1 capacity) (9 x 4 = 36)
With 15 DSPs but only a single E1 circuit that is 30 high complexity calls. (15 x 2 = 30)
With 15 DSPs and two E1 circuits that is 60 medium complexity calls. (15 x 4 = 60)