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Leased lines are an example of synchronous serial communication where one party provides the clocking

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for the communication.

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So in other words two devices will synchronize their clocks before data transmission takes place.

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So they will align or synchronize those clocks and agree on parameters for data transfer including the

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data interval between bits of data the Sea issue the issue or channel service unit data service unit

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commonly referred to as the seas you provides the clocking and is the master for the communication the

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right is acting as a slave and is receiving its clocking from the issue.

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So essentially before communication can start the two devices have to align their clocks or agree on

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the clock intervals to ensure that the data doesn't get corrupted.

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So here we have the terms data communication equipment or DCP and data terminal equipment or DTV the

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most in the communication is the C issue D issue and it's using its own internal clucking but the rudder

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which is the data terminal equipment or DTV uses the external clocking received from the DCP and will

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thus synchronize itself to the C issue D issue so the C issue D issue is the DC side of the connection

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and the rudder is the DTV side of the connection.

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So the DC which is the C issue D issue is providing clocking to the rudder which is the DTV and the

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DC also terminates the connection from the carrier and a connection is then made from the C issue D

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issue to the rudder some terms to understand therefore is customer premises equipment or CPE.

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This is the term that telcos or service providers use to refer to equipment that resides at the customer

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site.

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At the end of their connection.

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So once again in this example the C issue D issues at the customer site.

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The C issue D issue which is the DCP is connected in this example via a v 35 cable to the router and

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is providing clucking to the router so the C issue D issue which is the DC physically controls the speed

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and timing at which the router serial interfaces can send and receive but over the serial cable.

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You don't have the ability to configure the speed of your serial connection that is set by the issue

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DC and is generally set by the service provider on your behalf.

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The serial cable once again connects the C issue to the right interface.