We have been working to establish some sort of I/O, preferably RS232 with a PDP 11/05 After spending many hours on the problem we came up empty. The computer itself appears to be OK, the continuity cards are in the right places, the core RAM works, simple test programs function properly. For example entering code from 177700: 000240 000777 the computer will set the lowest address bit to 0-1-0-1 continuously. The current configuration is M9970 M7260 M7261 M920/H214 G110 G231 Grant UNIBUS bridge M7856 Grant Grant We don't have a device for 20ma current loop-ing so we're trying to use the M7856 for RS232 communications. We're not sure what ports to use with the M7856 while a M9970 is also installed, does a conflict exist? We have found the following resources and worked through what info was provided there http://www.shiresoft.com/pdp-11/11-10/index.html http://www.pdp-11.nl/per...terface/dl11w-info.html http://www.bitsavers.org...-DL11W-OP-001_May77.pdf If anyone on this list can assist with diagnostic steps it would be greatly appreciated. For example an octal listing for a character echo program. Please contact me directly. We're not sure what port to use for RS232, the default teletype port seems to be 60. I think we're close, and it's also possible that there is a problem with the card. The switch settings appear to be OK. Thanks Bill Degnan

The current configuration is M9970 M7260 M7261 M920/H214 G110 G231 Grant UNIBUS bridge M7856 Grant Grant We don't have a device for 20ma current loop-ing so we're trying to use the M7856 for RS232 communications. We're not sure what ports to use with the M7856 while a M9970 is also installed, does a conflict exist?