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New Member

2501/2514 routers, USR Courier, sync serial and v.25bis dialing

Hi all!

We're trying to connect few routers using conventional switched telco channels and USR Courier modems in syncronous mode.

Modem documentation shows they support v.25bis signalling for dialing in byte-oriented BSYNC and bit oriented HDLC modes, so as cisco 2500 docs shows that dialer in-band command given in serial interface configuration mode activates v.25bis HDLC based version.

So we switched modems into the sync HDLC based v.25bis dialing modes: AT&F1&M7&W

And configured cisco routers:

interface Serial 1

ip address unnumbered ethernet 0

dialer in-band

dialer-group 1

dialer string PHONENUMBER

dialer-list 1 protocol ip permit

ip route Serial 1

Next, we activated debug dialer and tried to ping OUTSIDEIP, and debug information shows dialer has dialing that PHONENUMBER but nothing realy happened...

Next command we tried was show interface serial 1 command that showed:

Serial 1 is up(spoofing), line protocol is up(spoofing)


X input errors, X CRC, 0 frame, 0 overrun, 0 ignored, 0 abort


What is the matter of that CRC errors detected and how to fix them?

Thanks in advance,


New Member

Re: 2501/2514 routers, USR Courier, sync serial and v.25bis dial

I think Syncrosous Serial port can not be used for dial in/out purpose.

Only Async port or Sync/Async port configured as Asyinc can be user.

this may be usefull.

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