Question : Problem: Cisco 1602 DTE async serial link problem

We have a couple of Cisco routers at the end of an HDLC leased line.  We are using Service provider DTUs to terminate the line, and have CAB-X21-MT cables connected to these devices on the serial port.

The problem is that the serial port is up, but the routers (1602s) say that the line protocol is down.  The service providers (who are not too much help) say that we need to put the routers into DTE mode in order that they obtain their clock signal from the ir network centre's clocking equipment.  How do you do this on a 1602 router?

Thanks

Answer : Problem: Cisco 1602 DTE async serial link problem

I've cut out the things that I would be looking at. First the IP address/mask of a point-to-point link looks odd, but that will not affect the line protocol.

>
interface Serial1
description RCN
ip address 133.133.90.1 255.255.240.0
>

>
Serial1 is up, line protocol is down
 Encapsulation HDLC, loopback not set, keepalive set (10 sec)
     5 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 5 abort
    233 packets output, 5969 bytes, 0 underruns
    0 output errors, 0 collisions, 78 interface resets
    0 output buffer failures, 0 output buffers swapped out
    0 carrier transitions
    DCD=up  DSR=up  DTR=up  RTS=up  CTS=up
>

Here we see 5 input errors that could indicate service provider issues. We also see all of your signalling is up making layer 1 good. Layer 2 is now suspect. Are you sure that this is not frame-relay?

>There is some ServProv equipment in between ...

Try this on one end and see what happens:
!
Interface serial 1
 no keepalive
!

>
QUICC Serial unit 1
...
DTE V.11 (X.21) serial cable attached.
>
Here is evidence for your service provider that you are indeed set for DTE.