PURPOSE: To reduce the transmission data quantity and then to economize the terminal units by memorizing temporarily the characters or the foreign letters featuring a low frequency plus the special patterns into the extension pattern memory.

CONSTITUTION: Processor 72 of terminal unit B decodes the codes sent from center unit A into either of the fundamental characters, fundamental patterns or foreign letters and extension patterns. In case the codes sent in are the fundamental character or fundamental pattern codes, the display patterns are obtained through fundamental character memory part 79 and fundamental pattern memory part 81 respectively. While the codes are the foreign letter or extension pattern codes, the foreign letter pattern or extension pattern sent from unit A separately is memorized in foreign letter pattern memory part 80 or extension pattern memory part 82. And the display patterns are obtained from these memory parts. Then the pattern corresponding to the code is displayed on display device 84 under the control of processor 72.