Ccna routing and Switching Complete Study Guide

Serial Transmission

WAN serial connectors use serial transmission, something that takes place 1 bit at a time 

over a single channel.

Older Cisco routers have used a proprietary 60-pin serial connector that you have to 

get from Cisco or a provider of Cisco equipment. Cisco also has a new, smaller proprietary 

serial connection that’s about one-tenth the size of the 60-pin basic serial cable called the 

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Cabling the Serial Wide Area Network 

895

smart-serial. You have to verify that you have the right type of interface in your router 

before using this cable connector.

The type of connector you have on the other end of the cable depends on your service 

provider and its particular end-device requirements. There are several different types of 

ends you’ll run into:

 

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EIA/TIA-232—Allowed speed up to 64 Kbps on 24-pin connector

 

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EIA/TIA-449

 

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V.35—Standard used to connect to a CSU/DSU, with speeds up to 2.048 Mbps using a 

34-pin rectangular connector

 

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EIA-530

Make sure you’re clear on these things: Serial links are described in frequency, or cycles per 

second (hertz). The amount of data that can be carried within these frequencies is called band-

width. Bandwidth is the amount of data in bits per second that the serial channel can carry.