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Telcos or service providers offer leased lines with different speeds.

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However you as a customer conscious pick some arbitrary speed.

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The speeds of leased lines follow the standards of older technology in the US it's called to the T carrier

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system and in other parts of the world.

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It's called the E carrier system.

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This comes originally from Alexander Graham Bell and the way that analog voice is digitized.

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So as an example when you speak it's an analog signal and you sending sound waves through the air but

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that gets digitized using something called the Night quest theorem and your analog voice is converted

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into a 64 kilobytes per second stream using a technology called time division multiple axing a single

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voice call.

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In most parts of the world using older technology such as ISDN is a 64 kilobytes per second.

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In the US you'll typically find 56 kilohertz per second when bonded together.

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Speeds can be increased so as an example a popular one is a T1 which consists of 24 64 kilohertz per

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second sessions plus eight kilobytes per second for overhead in a single connection or single leased

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line which provides one point five four megabits per second.

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Don't worry too much about the details but for example a D 0 or digital signal level 0 provides 64 kilohertz

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per second at t1 consists of 24 64 kilohertz per second sessions plus 8 kilobytes per second overhead

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giving you one point five four megabits per second.

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So this is 24 DS zeros plus eight kilobytes overhead giving you a T1 speed of one point five four megabits

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per second.

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That's a standard used in the US in Europe as an example.

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We have an E 1 rather than a T1 which gives you just over 2 megabits per second.

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So two point zero for eight and that consists of 32 DSL rows or 32 64 kilobytes per second channels

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a D 0 or digital signal level 0 is a 64 kilobytes per second channel a T1 consists of 24 channels each

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providing 64 kilobytes per second.

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Some other US examples at T2 is for T1 lines provide 6 megabits per second at T3 is 28 T1 lines providing

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48 megabits per second at T4 consists of 168 T1 lines giving you 274 megabits per second in Europe and

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each one is just over 2 megabits per second.

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E 2 is 8 megabits per second E 3s 34 megabits per second and an E 4 is 140 megabits per second.

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If you're going to remember anyone a t1 is one point five four four megabits per second and an E one

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is two point zero for eight megabits per second.

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So the easy issue dishy which is acting as the DCI e is using clocking to control when the router sends

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data and it also is configured for the relevant speed of the connection.

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So the DC controls the speed of the serial connection and the rudder is controlled by the clocking signals

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that it receives from the DC.

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This issue tells a writer went to send and receive bits.

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The rudder will only send and receive bits when instructed to by the DCP because of the clocking that

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the DC is providing on the cable.