manually restored using such punches. The ASCII character code included a special DELETE or DEL character defined as all holes punched out (code 7F), allowing an erroneous character to be canceled by punching extra holes. As punched tape technology became obsolescent in the 1980s, the manual tape repair tools became rare. Multiple-hole punches Multiple-hole punches typically place a pattern of holes along one edge of sheets of paper, allowing the pages to be bound together. The most common use for multi-hole punched paper is with a ring binder. A book-like cover is fitted with retaining rings matching the pattern of the punched holes. The rings may be split open, paper sheets threaded onto them, and then the rings closed again. A variety of hole patterns are in use for ring bindings. In much of the world, two-hole and four-hole punches consistent with ISO 838 are the norm. In the US, the three-hole punch is most common. See . There are other binding techniques which use hole punching. Coil binding uses a spring-like coil, threaded into the punched holes. Comb binding uses a plastic strip with "fingers" that clip into the punched holes. Both use their own types of specialized hole punches. Comb binding typically punches 19 or 23 rectangular holes (for letter and A4 paper sizes, respectively). History The origins of the hole punch date back to Germany via Matthias Theel, where two early patents for a device designed to "punch holes in paper" have since been discovered. Friedrich Soennecken filed his patent on 14 November 1886, for his Papierlocher für Sammelmappen, a multiple-hole punch and office supply product. A Google Doodle was used on 14 November 2017 to celebrate the 131st anniversary of the hole punch. The first record for a single-hole puncher—a ticket punch—was published in 1885, when Benjamin Smith helped create a spring-loaded hole puncher that had a receptacle to collect the chads. Smith dubbed it the “conductor’s punch”. A later paper punch was refined in 1893 by Charles Brooks, and it was referred to as a ticket punch due to its early role in punching train tickets as trains became increasingly popular and common between 1850 and 1900. Concerns have risen about the lifespan of the hole punch as most paper documents are now online, making the use of it irrelevant. Standards Multiple standards exist for the number and position of holes on multi-punched sheets. International