Multiplexer, Remote Access, DSU, RS-232, LAN & WAN Products from DCB

What is a Statistical Multiplexer?
Statistical multiplexers make it possible for multiple RS-232 devices to share a single data line. They also perform error correction to insure error-free transmissions. The term "statistical" refers to their ability to take advantage of the intermittent usage statics of most RS-232 devices (and all PC and terminal users). Because keyboards are idle a large part of each second with no one typing and no data being sent from the computer, each PC or terminal often averages less than 5% of its potential data rate. Statistical multiplexers allow the sum of the PC and terminal rates to exceed the composite link speed between the multiplexers.
The illustrations show a system without statistical multiplexers and how the same system would be configured with statistical multiplexing.

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DCB manufacturers statistical multiplexers with two to thirty-two asynchronous ports that use either synchronous or asynchronous composites (the line between the two multiplexers), and that use either propriatary or frame relay protocols between the units.
DCB also builds multi-drop and multi-point statistical multiplexers. These systems allow multiple remote sites to all communicate with a single multiplexer at a host site when using multi-point or multi-drop wide area networks such as radios, multi-drop DDS lines, or frame relay.

Statistical multiplexers were developed to meet the needs of terminal (and later PC) users. In the last few years, they have found new applications in many fields of machine-to-machine communications. It is now common to see statistical multiplexer networks with no PC or terminal connected. Some common uses are sharing one line between multiple point-of-sale terminals (cash registers), printers, networked computers using PPP or SLIP, lottery machines, SCADA systems, gaming machines, or process control equiment.

In some cases, routed networks share wide area network (WAN) links with older terminal based networks by conecting a router on one port of an older statistical multiplexer network. This allows simultaneous use of remote terminals along with LAN workstations for email and provides an orderly transition path from terminals to LAN based workstations networks.
Most statistical multiplexers use a proprietary protocol on the "composite line" between the two units. At DCB, we've also added frame relay as a composite protocol. This allows DCB multiplexers to operate over a native frame relay point-to-point or point-to-multipoint network.

Most statistical multiplexers also require a full duplex link between the two units. DCB has a line of data concentrators (special breed of statistical multiplexer) that function over a simplex or half-duplex link. This system works more efficiently over radio and satellite links.

DCB has been building statistical multiplexers since 1981. Along with the expected incremental improvements of faster speeds, open standards, lower cost, and more processing power; many unique features have been added to our statistical multiplexer line. For example, many of our statistical multiplexers support "AT command spoofing". This allows Windows95 PCs and other workstations to use PPP connections through a multiplexed WAN link. This feature is often used with frame relay to extend LAN connectivity to PCs at multiple locations with no ethernet cards or routers. Many other features have been added to enhance ease of configuration, problem diagnosis, remote training, and performance.

Links to DCB multiplexer product datasheets...
Link to other DCB products.
Link to other DCB educational material.

Data Comm for Business Inc.
2949 County Road 1000 E
Dewey, Il 61840 Voice: 217-897-6600
Toll Free: 800-4-DCB-NET
Toll Free: 800-432-2638 Email: Contact Page
Web: www.dcbnet.com
Fax: 217-897-8023

All DCB web pages copyright ©1995- Data Comm for Business, All rights reserved.
EtherPath®, EtherSeries®, EtherPoll®, EtherBridge® and EtherModem® are Registered Trademarks of Data Comm for Business, Inc.

What is a Statistical Multiplexer?		Statistical multiplexers make it possible for multiple RS-232 devices to share a single data line. They also perform error correction to insure error-free transmissions. The term "statistical" refers to their ability to take advantage of the intermittent usage statics of most RS-232 devices (and all PC and terminal users). Because keyboards are idle a large part of each second with no one typing and no data being sent from the computer, each PC or terminal often averages less than 5% of its potential data rate. Statistical multiplexers allow the sum of the PC and terminal rates to exceed the composite link speed between the multiplexers. The illustrations show a system without statistical multiplexers and how the same system would be configured with statistical multiplexing.
		.

		.
		DCB manufacturers statistical multiplexers with two to thirty-two asynchronous ports that use either synchronous or asynchronous composites (the line between the two multiplexers), and that use either propriatary or frame relay protocols between the units. DCB also builds multi-drop and multi-point statistical multiplexers. These systems allow multiple remote sites to all communicate with a single multiplexer at a host site when using multi-point or multi-drop wide area networks such as radios, multi-drop DDS lines, or frame relay. Statistical multiplexers were developed to meet the needs of terminal (and later PC) users. In the last few years, they have found new applications in many fields of machine-to-machine communications. It is now common to see statistical multiplexer networks with no PC or terminal connected. Some common uses are sharing one line between multiple point-of-sale terminals (cash registers), printers, networked computers using PPP or SLIP, lottery machines, SCADA systems, gaming machines, or process control equiment. In some cases, routed networks share wide area network (WAN) links with older terminal based networks by conecting a router on one port of an older statistical multiplexer network. This allows simultaneous use of remote terminals along with LAN workstations for email and provides an orderly transition path from terminals to LAN based workstations networks. Most statistical multiplexers use a proprietary protocol on the "composite line" between the two units. At DCB, we've also added frame relay as a composite protocol. This allows DCB multiplexers to operate over a native frame relay point-to-point or point-to-multipoint network. Most statistical multiplexers also require a full duplex link between the two units. DCB has a line of data concentrators (special breed of statistical multiplexer) that function over a simplex or half-duplex link. This system works more efficiently over radio and satellite links. DCB has been building statistical multiplexers since 1981. Along with the expected incremental improvements of faster speeds, open standards, lower cost, and more processing power; many unique features have been added to our statistical multiplexer line. For example, many of our statistical multiplexers support "AT command spoofing". This allows Windows95 PCs and other workstations to use PPP connections through a multiplexed WAN link. This feature is often used with frame relay to extend LAN connectivity to PCs at multiple locations with no ethernet cards or routers. Many other features have been added to enhance ease of configuration, problem diagnosis, remote training, and performance. Links to DCB multiplexer product datasheets... Link to other DCB products. Link to other DCB educational material.



Data Comm for Business Inc. 2949 County Road 1000 E Dewey, Il 61840	Voice: 217-897-6600 Toll Free: 800-4-DCB-NET Toll Free: 800-432-2638	Email: Contact Page Web: www.dcbnet.com Fax: 217-897-8023
All DCB web pages copyright ©1995- Data Comm for Business, All rights reserved. EtherPath®, EtherSeries®, EtherPoll®, EtherBridge® and EtherModem® are Registered Trademarks of Data Comm for Business, Inc.