Network adapters mystery

I've got my VAXstation and PC/Linux box connected via ethernet and TCP/IP at last ! And offcourse the problems I had - were on the PC side... VMS config was OK since first time :) But there was one mystery: The network not worked with Compex NE2000 clone adapter. When I replaced it with Compex ENET16/U adapter configured as NE2000 everything is OK... does anybody has any idea ? (I'm sure that first adapter was good, I've tested it) Was there any changes in ethernet specification that could make that new (1996 - second adapter was 1992) adapter incompatible with VAXstation ? And by the way - I got offer of "microVAX 3600 in 3500 case" I have no idea what it may mean - could it be 3600 put in small 3500 cabinet ? Is it possible ? (the offer is interesting anyway - its 3600 running VMS 5.5 + DECserver 200 + DELNI +4 VT320 + VT340 for free - I'm thinking where to put the stuff...) Maciek Szymanski