In our office we have a leased line connection to the ISP, and we are using 2500 series router with two serial ports and one Ethernet port. one serial port is connected to leased line and the other we have connected to external ISDN TA. The idea is, we want to use the second serial port for dial up purpose as a backup for the first serial port through ISDN TA. We are unable to do this. Please suggest the solution for this.
Wais Ahmed S