Complex sentence: The space is considered to be "both" a graphic character and a control character in ISO 646; this is probably due to it having a visible form on computer terminals but a control function (of moving the print head) on teletypes.
Split into simpler sentences: The space is considered to be "both" a graphic character and a control character. This is probably due to it having a visible form on computer terminals but a control function (of moving the print head) on teletypes.