When choosing a printer for your business, you must match the device’s capabilities to the volume and type of documents you print. When you add a new printer to your company’s hardware resources, you need a device that also supports your office’s computers, operating systems, and connection capabilities. The most common printer connections have changed as computer and output hardware have evolved to accommodate faster transfer of increasingly large files.
Serial connections make use of a 25- or 9-pin trapezoidal-shaped port and a single-wire cable that sends data bits one at a time. These straightforward, slower connections excel at handling long-distance cable runs of 25 to 100 feet without data loss. Early Apple Macintosh computers had round serial interfaces that ran at faster speeds than their PC counterparts. Some serial printers continue to function using serial-to-USB adapters to connect to modern computers that lack serial ports.
Centronics, or parallel, data interfaces were introduced in 1970 and quickly replaced serial as a printer connection on PCs. Parallel ports are classified into three types: unidirectional, bidirectional, and fast parallel, based on whether they transmit data in one or two directions and at what speed. Parallel interfaces transfer more information faster than serial devices because their data is carried along eight wires, but they cannot maintain the integrity of that data flow over long distances. Although some new printers still use parallel connections, the protocol has been dormant since the advent of USB.
At the time of publication, the most common connection protocol for non-networked printing devices was the Universal Serial Bus, or USB. USB, which was first introduced in the late 1990s, provides connectivity for a wide range of devices, some of which draw power and transfer data through the same connector. A 4-pin square connector on the end of USB printer cabling typically plugs into your computer. Unlike its predecessors in the history of printer connections, USB supports hot-swapping of components, allowing you to add or remove them from your computer without shutting it down.
Networked printers typically rely on an Ethernet connection, which employs cabling similar to that used to connect landline telephones to wall outlets. A four-wire RJ-45 connector is used for this hot-swappable protocol. When compared to other connection options, Ethernet has the greatest range, allowing for cable runs of up to 300 feet without the use of hubs or repeaters to maintain signal strength. Most printers that include an Ethernet interface also include a USB or other connection protocol.