Serial communication products are used in industrial and commercial systems to transmit data bit-by-bit, or sequentially, over a single wire. There are several major categories of serial communication products. Serial servers allow serial devices to be connected directly to a local area network (LAN) or wide area network (WAN) without the use of a personal computer (PC). Serial hubs allow the transparent connectivity of serial devices such as industrial instruments, point-of-sale (POS) terminals, and barcode printers with LANs and WANs. Serial adapters provide one or more serial ports to a host computer. Serial data converters are used to convert data from one serial standard to another. Serial routers are protocol-dependent devices that connect subnetworks. Serial multiplexers are telecommunications devices that funnel multiple signals onto a single channel. Other types of serial communication products are also commonly available.