Verilink AS2000: The Basics (880-502981-001) Product Manual Instrukcja Użytkownika Pobierz pdf (Strona 28)

System Information

2-12 Verilink Access System 2000: The Basics

Figure 2-7 DCE to DTE Timing

Crossover

Connection

Use a crossover connection whenever transmit and receive signals

go to the opposite leads for an application, such as tail circuits.

The receive data from device A becomes the transmit data to device

B. The receive data from device B becomes the transmit data to

device A.

In a crossover circuit, each DCE relinquishes control of the transmit

path to the other DCE. Clock signals are also cross-connected. The

DCE device outputs receive data at the rate which data is received.

See Figure 2-8.

Figure 2-8 Crossover Connection

Synchronous devices output a receive clock that is in phase with

receive data. Since receive data becomes transmit data to the tail-

circuit DCE, it uses the receive clock from the main circuit DCE to

sample correctly. In most crossover connections, both devices are

configured to use the receive clock as the transmit clock. The CSU

and DSU timing settings depend on the location of the master

clock.

Clock

Signal

DSU

rx rd tt td

DSU

rx rd tt td

1 2 ... 23 24 25 26 27 28 29 30 31 32 33 ... 178 179

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Verilink AS2000: The Basics (880-502981-001) Product Manual Instrukcja Użytkownika Strona 28