Serial Link speeds

jjakobsenjjakobsen Posts: 3Registered Users ■□□□□□□□□□
How do you determine what clock rate speed to use on a serial interface when setting up a back-to-back (DCE/DTE) connection on lab routers?

Is there a list of serial cables and their speeds?


  • alan2308alan2308 Senior Member Ann Arbor, MIPosts: 1,854Member ■■■■■■■■□□
    In a lab environment, it doesn't matter, use which ever speed you want. The cables aren't a factor. Besides that, you're probably not going to notice the difference anyway.

    In an production environment, you're not going to be connecting routers together with back to back serial cables, you're going to be connecting them to things like a T1 DSU/CSU or an Adtran. What you're connecting it to will determine which speed you should use.
  • jjakobsenjjakobsen Posts: 3Registered Users ■□□□□□□□□□
    So setting the clock rate at 56000 on the DCE end router should be ok?
  • alan2308alan2308 Senior Member Ann Arbor, MIPosts: 1,854Member ■■■■■■■■□□
    Yes, as long as both routers support a speed, you're fine using it.
  • Forsaken_GAForsaken_GA Posts: 4,024Member
    The normally accepted clock rates are as follows:

    1200, 2400, 4800, 9600, 19200, 38400, 56000, 64000, 72000, 125000, 148000, 250000, 500000, 800000, 1000000, 1300000, 2000000, 4000000, or 8000000

    IOS will adjust whatever number you put in to the nearest value your hardware can support. In most cases 56000 is fine
  • jjakobsenjjakobsen Posts: 3Registered Users ■□□□□□□□□□
    Perfect, thanks everyone
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