Even the Windows 3.11 AMSTRAD I know of accomodated an ethernet card, but such technology is something I can't assist with except to prove that it worked in its day.
It's too bad you didn't note an OS so I can only suggest the above and DCC as noted at http://www.wown.com/j_helmig/dccmain.htm
Is the forum tip not showing for you either?
Bob
Recently I bought a new PC With Win xp SP2 Home edition. My old CPC is an AMSTRAD 6128. Is there any way to connect them or should I put the ASTRAD at the Museum ?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic