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P-660H/HW-T Series User’ Guide
Introduction to DSL
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Introduction to DSL
DSL (Digital Subscriber Line) technology enhances the data capacity of the existing twisted-
pair wire that runs between the local telephone company switching offices and most homes
and offices. While the wire itself can handle higher frequencies, the telephone switching
equipment is designed to cut off signals above 4,000 Hz to filter noise off the voice line, but
now everybody is searching for ways to get more bandwidth to improve access to the Web -
hence DSL technologies.
There are actually seven types of DSL service, ranging in speeds from 16 Kbits/sec to 52
Mbits/sec. The services are either symmetrical (traffic flows at the same speed in both
directions), or asymmetrical (the downstream capacity is higher than the upstream capacity).
Asymmetrical services (ADSL) are suitable for Internet users because more information is
usually downloaded than uploaded. For example, a simple button click in a web browser can
start an extended download that includes graphics and text.
As data rates increase, the carrying distance decreases. That means that users who are beyond
a certain distance from the telephone company’s central office may not be able to obtain the
higher speeds.
A DSL connection is a point-to-point dedicated circuit, meaning that the link is always up and
there is no dialing required.
Introduction to ADSL
It is an asymmetrical technology, meaning that the downstream data rate is much higher than
the upstream data rate. As mentioned, this works well for a typical Internet session in which
more information is downloaded, for example, from Web servers, than is uploaded. ADSL
operates in a frequency range that is above the frequency range of voice services, so the two
systems can operate over the same cable.
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Страница 10: ...P 660H HW T Series User Guide 9 Customer Support ...
Страница 32: ...P 660H HW T Series User Guide 31 List of Figures ...
Страница 38: ...P 660H HW T Series User Guide 37 List of Tables ...
Страница 42: ...P 660H HW T Series User Guide 41 Introduction to DSL ...
Страница 62: ...P 660H HW T Series User Guide 61 Chapter 3 Wizard Setup for Internet Access ...
Страница 90: ...P 660H HW T Series User Guide 89 Chapter 5 Wireless LAN ...
Страница 132: ...P 660H HW T Series User Guide 131 Chapter 10 Firewalls ...
Страница 162: ...P 660H HW T Series User Guide 161 Chapter 13 Remote Management Configuration ...
Страница 176: ...P 660H HW T Series User Guide 175 Chapter 14 Universal Plug and Play UPnP ...
Страница 182: ...P 660H HW T Series User Guide 181 Chapter 15 Logs Screens ...
Страница 196: ...P 660H HW T Series User Guide 195 Chapter 16 Media Bandwidth Management Advanced Setup ...
Страница 208: ...P 660H HW T Series User Guide 207 Chapter 17 Maintenance ...
Страница 218: ...P 660H HW T Series User Guide 217 Chapter 19 Menu 1 General Setup ...
Страница 222: ...P 660H HW T Series User Guide 221 Chapter 20 Menu 2 WAN Backup Setup ...
Страница 226: ...P 660H HW T Series User Guide 225 Chapter 21 Menu 3 LAN Setup ...
Страница 230: ...P 660H HW T Series User Guide 229 Chapter 22 Wireless LAN Setup ...
Страница 236: ...P 660H HW T Series User Guide 235 Chapter 23 Internet Access ...
Страница 250: ...P 660H HW T Series User Guide 249 Chapter 25 Static Route Setup ...
Страница 254: ...P 660H HW T Series User Guide 253 Chapter 26 Bridging Setup ...
Страница 270: ...P 660H HW T Series User Guide 269 Chapter 27 Network Address Translation NAT ...
Страница 286: ...P 660H HW T Series User Guide 285 Chapter 29 Filter Configuration ...
Страница 306: ...P 660H HW T Series User Guide 305 Chapter 32 System Information and Diagnosis ...
Страница 318: ...P 660H HW T Series User Guide 317 Chapter 33 Firmware and Configuration File Maintenance ...
Страница 324: ...P 660H HW T Series User Guide 323 Chapter 34 System Maintenance ...
Страница 328: ...P 660H HW T Series User Guide 327 Chapter 35 Remote Management ...
Страница 338: ...P 660H HW T Series User Guide 337 Chapter 36 IP Policy Routing ...
Страница 342: ...P 660H HW T Series User Guide 341 Chapter 37 Call Scheduling ...
Страница 354: ...P 660H HW T Series User Guide 353 Chapter 38 Troubleshooting Figure 233 Security Setting ActiveX Controls ...
Страница 358: ...P 660H HW T Series User Guide 357 Appendix A ...
Страница 360: ...P 660H HW T Series User Guide 359 Appendix B ...
Страница 384: ...P 660H HW T Series User Guide 383 Appendix D ...
Страница 388: ...P 660H HW T Series User Guide 387 Appendix F ...
Страница 394: ...P 660H HW T Series User Guide 393 Appendix G ...
Страница 398: ...P 660H HW T Series User Guide 397 Appendix H ...
Страница 401: ...P 660H HW T Series User Guide Appendix I 400 ...
Страница 402: ...P 660H HW T Series User Guide 401 Appendix I ...
Страница 456: ...P 660H HW T Series User Guide 455 Appendix M ...