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Figure 12.1 |
An illustration of digitization using eight values. Each vertical line represents an integer value chosen for one sample. |
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Figure 12.2 |
Illustration of a digital circuit with a DSU/CSU on each end. The DSU/CSU converts between the digital standards used in the telephone system and those used by computer vendors. |
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Figure 12.3 |
Data rates of popular digital circuit standards used in North America and Europe. |
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Figure 12.4 |
An inverse mux using two T1 circuits to provide a connection with twice the capacity. Inverse multiplexing is attractive economically for intermediate capacities because two T1 circuits are much less expensive than a T3 circuit. |
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Figure 12.5 |
Data rates of digital circuits according to the STS hierarchy of standards. |
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Figure 12.6 |
Illustration of an STS-1 SONET frame with 810 octets divided into 9 rows of 90 columns. Octets at the beginning of each row provide clock synchronization and maintenance information. |
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Figure 12.7 |
ADSL modems connected to existing local loop wiring. The modems can use a pair of wires simultaneously with analog telephone service. |
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Photo 3_058 |
Two Ascend Pipeline ISDN modems. |
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Photo 3_059 |
An Ascend Pipeline ISDN modem. |
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Photo 3_060 |
An Ascend Pipeline ISDN modem. |
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Photo 6_029 |
A Fujitsu DSL modem. |
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Photo 7_002 |
A Cisco 673 DSL modem. |
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Photo 7_006 |
Cisco DSL products, including DSLAM and DSL modem. |
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Photo 7_008 |
A twisted pair interface card for a Cisco DSLAM. This device is the modem in the service provider's DSLAM, typically located in the service provider's office. |
