I am studying for the CCIE voice and would like to set up a PSTN switch in my home lab. I have three ISRs that I would like phones in each "branch" to be able to call any other branch via T1 PRI. Currently, each of my ISRs have a VWIC-1MFT-T1, and would like to have the cards terminate to VWIC-1MFT-T1 cards on the PSTN switch. Can someone recommend a low-cost solution for the PSTN switch? For those familiar with or studying for the exam, can you recommend a method of connecting the gatekeeper to this setup as well? Any help or wisdom is appeciated.