Serial connection problems, including interface and line protocol status, output drops, input drops, input errors, interface resets, and carrier transitions

[TCC_2]

Core Issue

These are some of the reasons these issues occur:

• Clocking problems
  
• Faulty cabling 
  
• A TELCO line is down.
  
• Keepalives are not sent by a remote router. 
• Noisy line

Resolution

For a workaround, perform these steps:

1. Issue the Router # sh interfaces serial < ID > command in EXEC mode.
   
2. From the output, check the first line. This gives the interface status.

For additional information, refer to table 15-1 in the Serial Lines: show interfaces serial Status Line Conditions section of Troubleshooting Serial Line Problems.