I/O device on the DRTE design were extremely limited, consisting of a Flexowriter for output, and a paper tape reader at about 600 CPS for input. In particular, the system added a hardware binary-to-decimal/decimal-to-binary converter that was implemented inline with the I/O systems. This allowed the paper tape to be punched in decimal codes which would be converted invisibly into binary and stored in memory while being read. The reverse was also true, allowing the machine to print the contents of memory directly to tape again. The system was tuned so that the machine could read or write data essentially for free; that is, the system could read and store data exactly as fast as the paper tape could feed it.