Magazine Article | January 1, 2002

A Hub Of Connectivity

Source: Innovative Retail Technologies

A serial hub is not just any port in a storm. The technology helps reconcile the growing number of peripherals and the shrinking number of connection points.

Integrated Solutions For Retailers, January 2002

Innovations in serial I/O (input/output) connectivity are shifting from server-based solutions to the use of serial hubs. Serial hubs are network-enabled devices that provide serial ports for use by server-based applications. These hubs work in concert with drivers that are loaded on a server to capture port requests and redirect those requests to peripherals across the network. Just as network print servers made it possible to share parallel printers, the advent of serial hubs makes it possible to share serial peripherals such as modems, bar code scanners, card readers, and receipt printers. With this technology, applications are able to access network-based serial devices as if they are locally attached.

Serial Hubs Create Connection To IP
Pervasive IP (Internet protocol) networks have made global communications a cost-effective reality, but countless serial devices are unable to attach to this global network. Serial hubs provide a quick, simple, and cost-effective means to access local or remote devices through standard TCP/IP. The emergence of large centralized computing centers has driven a need for remote I/O devices. Serial hubs transport serial I/O data transparently across IP-based networks making them ideal for server-based applications to remotely access peripherals. Serial hubs also make use of industry-standard Ethernet cabling to tunnel serial data across networks. Structured cabling lowers project costs while improving maintainability and eliminates the need for point-to-point and long-haul serial cables. The benefit in eliminating these cabling nightmares is reduced cable clutter and costs.

Serial hubs are deployed in retail/POS (point of sale), hospitality, industrial automation, security/access control, console port access, and a wide variety of applications that require a cost-effective, reliable means to connect and manage serial devices over Ethernet. There has been a strong increase in demand for serial hubs as more customers seek to attach serial devices to the network. A key requirement is the ability to manage ports, especially those installed at remote locations.

External PC Devices Proliferate
PC design is slowly evolving toward an architecture that permits peripheral devices to be added without disrupting the ongoing operation of the system. FireWire, Fibre Channel, USB (universal serial bus), and Bluetooth are all examples of this evolution. However, each of these new bus types is designed for specific applications. FireWire is geared toward video capture; Fibre Channel is geared toward high-speed mass storage; USB and Bluetooth are both geared toward I/O devices such as mice, keyboard, scanners, and printers. System bus expansion card slots are slowly disappearing as these external bus types grow in popularity. Some computers do not provide any internal system bus expansion slot, which illustrates a trend to add devices outside the computer or an "out-of-the-box" solution.

Computers are also decreasing in size. Low-profile computers are designed to take up as little as one or two rack units in height. The compact size of these computers leaves little room for internal expansion cards. Once again, serial hubs have emerged as the preferred means of access to serial devices from these systems. Also, a growing trend toward application servers has resulted in a wide rollout of thin client systems. Thin clients, which are designed to be compact in size, provide little room for internal expansion cards. Serial hubs complement thin clients for I/O intensive applications.

The real-world benefits offered by serial hubs, as well as trends in PC architecture and application development, have contributed to their rapid market acceptance. Because commercial connectivity requires robust interfaces such as RS-232, RS-422, and RS-485, devices that attach to these interfaces are here to stay. Serial hubs are the future means to connect these devices to tomorrow's PCs.