The simplest of printer sharing devices is a manual switch, also known as a mechanical switch or an A/B switch. Up to 6 PCs can share a single printer in such an arrangement. The switch must be physically set to give each user access to the printer. If the printer is busy, all other users must wait.
Close physical proximity of all users to the shared printer is the key to success of such a setup. All users should ideally be within sight or talking distance of one another to efficiently coordinate the switching of printer access from one user to another. Manual switches are most often manufactured with a fixed number of serial and /or parallel ports. Input (PC) and output (printer) ports are most often of a fixed number and not interchangeable.
An important incremental improvement on the manual switch is the simple electronic switch. This device is especially important if a laser printer is among the printers to be shared. The small voltage spike generated with physical switching of a manual switch is potentially damaging to a laser printer’s circuit boards. Electronic switches are often manufactured with built in software, which scans attached PCs for waiting printing jobs. User intervention is not necessary with these scanning electronic switches. User’s ether has immediate access to the printer or receives a “printer busy” message. As soon as the printer is free, the electronic switch automatically connects a waiting PC with the available printer. Buffered and no buffered printer shares, data switches, and data PBXs all use electronic switching.
For serial-to-parallel or parallel-to-serial conversion, a more expensive device, commonly known as a data switch, is a possible solution. Serial-to-parallel and parallel-to-serial conversion are also available in standalone conversion devices. Data switches also offer greater overall capacity in terms of expandability and total number of PCs and printers that can be attached, as well as more advanced features that will be discussed shortly.
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