Building Cabling Management Structured Cabling(电缆敷设) Plans esting Inexpensive just to test whether wires are connected properly More expensive to test for signal quality Documentation and Neatness Critical to avoid chaos in wiring 6-11
6-11 Building Cabling Management • Structured Cabling (电缆敷设) Plans • Testing – Inexpensive just to test whether wires are connected properly – More expensive to test for signal quality • Documentation and Neatness – Critical to avoid chaos in wiring
The public switched Telephone Network(PSTN)4 共交换电话网
The Public Switched Telephone Network (PSTN) 公 共交换电话网
Figure 6.4: Public Switched Telephone Network(PSTN Switching office Access Line(接入线) Central office Local Loop(本地回路) End office Single Twisted Pair Of Low Quality lr Customer Premises Customer Premises 客户驻地 (Residential) (Business) 6-13
6-13 Figure 6.4: Public Switched Telephone Network (PSTN) Customer Premises 客户驻地 (Residential) Customer Premises (Business) Switching Office Central Office End Office Access Line (接入线) Local Loop (本地回路) Single Twisted Pair Of Low Quality
Figure 6.4: Public Switched Telephone Network(PSTN Class 3 Switching Hierarchy Trunk Line (干线) Digital Class 4 Class 5 Class 5 End End Office Office 6-14
6-14 Figure 6.4: Public Switched Telephone Network (PSTN) Switching Hierarchy Trunk Line (干线) Digital Class 4 Class 3 Class 5 End Office Class 5 End Office
Figure 6.5: Trunk Line Technologies Connect pairs of switches Trunk line Speed North American Digita/ Hierarch 56 kbps(Dso Signaling) 56 kbps(sometimes 64 kbps) T1(DS1 Signaling) 1.544 Mbps T3 (DS3 Signaling) 44.7 Mbps CEPT Multiplexing Hierarchy 64 kbps 64 kbps E1 2.048 Mbps E3 34.4 Mbps Note: CEPT, Conference of European Postal and Telecommunication 我国采用此标准 6-15
6-15 Figure 6.5: Trunk Line Technologies Trunk Line Speed North American Digital Hierarchy 56 kbps (DS0 Signaling) 56 kbps (sometimes 64 kbps) T1 (DS1 Signaling) 1.544 Mbps T3 (DS3 Signaling) 44.7 Mbps CEPT Multiplexing Hierarchy 64 kbps 64 kbps E1 2.048 Mbps E3 34.4 Mbps Connect Pairs of Switches Note: CEPT, Conference of European Postal and Telecommunication 我国采用此标准