DEC VNswitch 900 100baseT PCB
VNswitch 900 Mid Range Board,
DRAM MH2M32CJJ-7 8MB 2x32 FP DRAM, 70nS, 5v.
S2 - Fits inside locking tab. It opens up when the module is pulled off the DEChub.
P2 - RJ45 port that is covered on the DVNEX.
LSI MIPS CNTRL - LR33300QC-25
P1 - LDM Port - Dedicated 10BaseT Ethernet port. Loads and upline dumps of an operational image. Wired as a straight-through connector.
S1 - Reset/Dump Button Used to either reset the module or perform an upline dump of the operational image, followed by a reset.
HALO MDQ-001 Thin Net Transceiver (TNT) datasheet
L2A0527 Custom ASIC device originally made by LSI (REI might know something)
VNswitch 900 Mid Range Board, Bottom 54-24831
DEC had something called the "Utopia" bus. My suspicion is the Philips FB2014BB FutureBus chip is just that. Notice the three LM317T voltage regulators on the left side. Must be for regulating the fans? Remember, on the other side, there are three LM339 voltage regulators as well.