There is no one set CSR assigned to the first DHV11... it depends on what else is in your system. The lowest address a DHV can be configured for is 17760020. Subsequent ones increase by 20(8). The vector also depends on what else is in the system. Since the uVaxIII has the config command, you might want to try using that, and enter all the devices on your system, and it will provide you with what the correct configuration should be according to the configuration rules. Just for the heck of it, I checked the RT-11 SYSGEN procedure to see what it uses for a default for the first DH-type interface, and that is 17760440. Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+