Datacom > Multiplexors

Local multiplexors extend the distance between computers and terminals or printers that are connected via customer-installed or telco-supplied cable.

Like line drivers, local multiplexors extend RS-232 communications and must be used in pairs. The difference between the two is that multiplexors merge several transmissions into one transmission over a single channel; line drivers generally transmit data over a single channel.

Local multiplexors operate over ordinary twisted-pair copper cable or fiber optic cable. Copper cable is typically used within buildings while fiber optic cable is the most common choice for connecting buildings in a campus environment. For in-building connections, copper cable is widely used because it’s comparatively inexpensive and easy to install. Your building might even have unshielded twisted-pair cable already in place.

The twisted-pair copper cable used for local multiplexors is run throughout buildings from the wallplates of each office or work area to a central wiring closet within the building. Wiring closets have centrally located punchdown blocks where all cables from the building are terminated. That way, when a connection needs to be changed or a new one needs to be made within the building, wiring can be easily rerouted on the punchdown blocks.

Selecting a local multiplexor.
When selecting a local multiplexor, keep in mind that copper-based multiplexors come in a vast array of types. You’ll find multiplexors available with RJ-11, RJ-45, or terminal block connections for your in-house wiring and with RS-232 connections for your computer equipment. All these multiplexors can be used to link a local device to a remote device within a building.

What is it?
Frame Relay is a type of packet-based switching technology that’s streamlined for speed. It was developed to solve communication problems that other protocols could not: large bandwidth efficiency for clumping (“bursty”) traffic, lower protocol processing, and high speeds.

What does it do?
Frame Relay provides a signal and data-transfer mechanism between the endpoints, or sites, of a network. It enables many users to share bandwidth, creating instantaneous bandwidth-on-demand (“BONDing”). It sends information in packets called frames that contain all the information necessary to route it to the correct destination. So in effect, each endpoint can communicate with many destinations over one access link to the network. And instead of being allocated a fixed amount of bandwidth, Frame-Relay traffic gets full bandwidth for short, bursty transmissions.

How does it work?
The Frame-Relay network contains user devices and network devices. The sending user device delivers the frames to the network. The network reads the addressing information on the frames and routes them to the proper destination user devices. Frame Relay assumes the data is error free, which cuts out a time-consuming step in the processing protocol. Therefore, the data travels much faster than with other, older technologies. Any error correction is done by the user devices (PCs, routers).

What are the benefits?
There are many benefits of Frame Relay: lower internetworking costs—with multiple logical connections over a single physical connection, you get lower equipment costs and access costs plus better performance; more network access; and less network complexity.

What equipment do I need?
Black Box has all the equipment you need to run Frame Relay. When used with a bridge or router and a CSU/DSU, our Frame-Relay Switches send your data across your WAN and implement the Frame-Relay interface. Our FrameRouter also gives you quick access to the Internet.

If you’re not sure which Frame-Relay device is best for your system, just call Tech Support at 724-746-5500, and press 1, 2, 3 to get the expert help of our Communications Team.