They were using good old fashioned wire in 1998. I think the switch to fiber optics was in 2000. The connectors to the CD changer are noticeably different. I think if you check the stickies in the w210 forum at benzworldDOTorg there is mention of the connector (color, etc). Sorry I don't remember off hand.

I upgraded to a Becker Monza (7882) which has a fuse and I think my old radio (Becker 1692) had a fuse as well but it's gone (sold). I guess the easiest thing would be to pull your radio and look since maybe the Alpines had fuses as well.