[WGoyer]

If you have 4 and 5 jumpered and 6,8,20 jumpered, there shouldn't be any alarms. You might check your null modem first or check it on another Fanuc control before declaring the port bad. All 10 mother boards that I've seen have two ports, although ALL of the three possible ports on a 10 are optional, so using the spare port might be a problem. I think most machines came with at least the first two turned on. The third one would be on the external board.
Warren
Uptime Electronics, Inc.

[Hepha3stus]

Thanks, I figured that there should be no alarms using the no handshake null modem (4 and 5 jumped and 6,8,20 jumped). That's why I figure my connection on the main board is fried. I have also checked the machine for other ports but did not find any. The maintenance manual shows that there is an option 1 card (A16B-1210-0350) that usually comes with the machine that also has the RS232 connecter. I think this is the board usually connected to the tape reader but my machine did not come with that feature. I just hope installing it won't require too many parameter changes!