barcode generator in vb.net 2010 Figure 2-33 GPS receiver on roof of CO. in Software

Maker Code 39 Full ASCII in Software Figure 2-33 GPS receiver on roof of CO.

Figure 2-33 GPS receiver on roof of CO.
Recognize USS Code 39 In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
ANSI/AIM Code 39 Printer In None
Using Barcode creator for Software Control to generate, create Code-39 image in Software applications.
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
Decoding Code 39 In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
Code 39 Full ASCII Generation In C#
Using Barcode generator for VS .NET Control to generate, create Code39 image in .NET applications.
SONET Basics
Generating Code 39 Full ASCII In VS .NET
Using Barcode creator for ASP.NET Control to generate, create Code 39 Extended image in ASP.NET applications.
Printing USS Code 39 In Visual Studio .NET
Using Barcode drawer for Visual Studio .NET Control to generate, create Code 39 image in .NET applications.
SONET Basics
Encoding ANSI/AIM Code 39 In VB.NET
Using Barcode maker for Visual Studio .NET Control to generate, create Code39 image in .NET framework applications.
Bar Code Creation In None
Using Barcode maker for Software Control to generate, create bar code image in Software applications.
Figure 2-34 BITS clock in CO.
Generating Code 3/9 In None
Using Barcode creation for Software Control to generate, create Code 39 Full ASCII image in Software applications.
Encoding EAN-13 In None
Using Barcode encoder for Software Control to generate, create EAN 13 image in Software applications.
from another multiplexer, potentially in another network, synchronized by a different primary clock reference, which means that some drift or jitter may occur between the two. The answer is actually quite simple. Multiplexers use a technique called loop timing or phase locked loop timing to ensure transmit and receive harmony. In loop timing, shown in Figure 2-35, each multiplexer uses its transmit clock s signal to provide timing to the received signal, telling the receiving circuitry when to look at the incoming bit stream. This ensures that although the muxes may be slightly out of whack with each other from a timing perspective, they will never be too far out of whack, thus guaranteeing that each receiving device in the network will be able to interpret the incoming information properly. Today, central-office timing models are still hierarchical. They rely on a primary-reference clock signal, but instead of a single-reference clock providing a timing source for all devices in North America, each office has a primary clock, as shown in Figure 2-36. Thus, the GPS signal provides guidance to the PRC, which in turn provides timing and synchronization accuracy to the higher-tier toll switches in the network. The toll switches provide a signal to the local switches and digital cross-connect systems,
Data Matrix 2d Barcode Printer In None
Using Barcode maker for Software Control to generate, create Data Matrix image in Software applications.
Barcode Generation In None
Using Barcode creation for Software Control to generate, create bar code image in Software applications.
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
2/5 Industrial Drawer In None
Using Barcode maker for Software Control to generate, create Code 2 of 5 image in Software applications.
Scan Bar Code In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
SONET Basics
GTIN - 12 Maker In Visual Studio .NET
Using Barcode encoder for ASP.NET Control to generate, create UPCA image in ASP.NET applications.
Painting EAN 13 In .NET Framework
Using Barcode generator for Reporting Service Control to generate, create UPC - 13 image in Reporting Service applications.
Figure 2-35 Loop timing.
Print Linear Barcode In Visual Studio .NET
Using Barcode creation for .NET Control to generate, create Linear image in VS .NET applications.
Decode Bar Code In Visual Studio .NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
2
Bar Code Creator In Objective-C
Using Barcode drawer for iPhone Control to generate, create barcode image in iPhone applications.
Barcode Printer In Visual Studio .NET
Using Barcode printer for Reporting Service Control to generate, create bar code image in Reporting Service applications.
Figure 2-36 GPS timing in modern network.
GPS Satellite
Toll Switch PRC Local Switch Toll Switch Local Switch Toll Switch Local Switch DCS
Toll Switch
which time the PBXs and lower-tier multiplexers. Thus, all devices in the office derive their timing from a single source. The PRC is considered to be a Stratum 1 clock, whereas the toll switches are Stratum 2, the local switches and DCSs are Stratum 3, and the PBXs and T1 multiplexers are Stratum 1. As one descends in the hierarchy, the stringency of absolute accuracy relaxes. This is not to say that the clocks are inaccurate as Einstein might have said, Everything is relative, my child. A Stratum 4 clock, for example, has no real requirements for accuracy; the clocks found in PCs are Stratum 4 and they wander all over the place in terms of accuracy. Stratum 3 clocks are a little bit better; standards require that they have less than 255 timing slips in the first 24-hour period following a loss of clock ref-
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
SONET Basics
SONET Basics
erence. Stratum 2, on the other hand, must have less than 255 slips in the first 86 days following a loss of synchronization signal. I d call that more accurate, wouldn t you Finally, a Stratum 1 clock, used as the primary source in an office, is typically a cesium or rubidium atomic clock that is so accurate that it will lose a single second of accuracy approximately once every 250,000 years good enough. Because of the speed at which they operate, all SONET networks require timing signals that are Stratum 3 or better. Otherwise, pointer justification and other functions that were discussed earlier will not take place with appropriate levels of accuracy.
SONET Synchronization
SONET relies on a timing scheme called plesiochronous timing. As I implied earlier, the word sounds like one of the geological periods that we all learned in geology classes (Jurassic, Triassic, Plesiochronous, Plasticene, and so on). Plesiochronous derives from Greek and means almost timed. Other words that are commonly tossed about in this industry are asynchronous (not timed), isochronous (constant delay in the timing), and synchronous (timed). SONET is plesiochronous in spite of its name (Synchronous Optical Network) because the communicating devices in the network rely on multiple timing sources and are therefore allowed to drift slightly relative to each other. This is fine because SONET has the ability to handle this with its pointer-adjustment capabilities. The devices in a SONET network have the luxury of choosing from any of five timing schemes to ensure accuracy of the network. As long as the schemes have Stratum 3 accuracy or better, they are perfectly acceptable timing sources. The five are discussed below.
Line timing: Devices in the network derive their timing signal from the arriving input signal from another SONET device. For example, an add-drop multiplexer that sits out on a customer s premises derives its synchronization pulse from the incoming bit stream and might provide further timing to a piece of CPE that is out beyond the ADM. Loop timing: Loop timing is somewhat similar to line timing; in loop timing, the device at the end of the loop is most likely a terminal multiplexer. External timing: The device has the luxury of deriving its timing signal directly from a Stratum 1 clock source.
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
Copyright © OnBarcode.com . All rights reserved.