I am receiving the following error from my 2620 after I connect a serial cable between it and a 2501.
"The CD2430 Controller is not responding, power cycle the router"
They are both using PPP encapsulation and the clock rate is set to 64000. I have also rebooted the router as suggested. The interface on the 2620 is a low speed serial. Thanks in advance for any help you can provide.