What patterns could be observed in this quantum entanglement thought experiment? Please see attached image below.

The DEVICE is beaming two streams of entangled particle pairs (B1 and B2) in opposite directions (e.g.: Particle no. 1 (p1) goes left, Particle no. 2 (p2) goes right, where p1 and p2 are making up an entangled particle pair).  Let us follow the left particle beam (B1) for now. When B1 encounters the Double Slit Apparatus (A1) in its way, an interference pattern will form on the Detector Screen (S1) behind.
There is a switchable Which-way Detector (D1) that can monitor Double Slit Apparatus (A1). If D1 is switched off, the interference pattern prevails; however, if D1 is active, the wave function collapses and draws a ballistic pattern over time.
My questions are:


*

*what pattern is detected by S2 if D1 is active?

*and what pattern emerges on S2 when it is turned off?


Thank you!
 A: Most importantly, the pattern detected at S2 will not depend on the detector D1.  Otherwise, this could be used for faster-than-light signalling, which is impossible within quantum mechanics.
Beyond that, what you will see at S2 will depend on which degree of freedom has been entangled.  Generally, one would expect to see an interference pattern, but if you manage to entangle a degree of freedom which relates to the slit taken by the photon, there will be no interference pattern.
A: When entangled photons are created in Bell-type experiments, it is their polarizations which are entangled. It is not clear to me that their positions or momenta are entangled in the same way. But anyway, engtanglement does not violate "no action at a distance" and in particular there is no way to see at location S1 what measurement is being made at location S2. Therefore it is clear that an interference pattern observed at location S2 cannot change according to how the photons are measured at location S1. 
A: If D1 is off on both sides will be interference pattern, may be shifted in phase.
If D1 is on there are no interference patterns on any side.
