Abstract: A system for interfacing central office telephone lines with internal facsimile machines. Roll-over lines are employed that automatically sequence up from the main facsimile telephone number as more and more facsimile transmissions arrive. Incoming and outgoing facsimile transmission data is placed in memory storage after being received and before being transmitted. The combination of roll-over and memory storage makes the system transparent to the outside sender, since all incoming facsimile transmissions dial the same main telephone number. Similarly, outgoing messages are transparent to the facsimile machine operators inside the company, since their messages are sent to the interface unit, stored in memory and then sent out over the next free facsimile telephone line.