Cisco PIX 501 VPN problem

I have tried both to manually configure a 501 for a site to site VPN using ipsec. When I am finished it never even attempts to connect (as well as I can figure). When I go under monitoring and ipsec it reports 0 encapsulated packets. The admin of the other network says he can’t even see any attempts to connect. I’ve checked the gateway IP a zillion times, as well as the pre-shared key. We’ve both confirmed everything possible in settings. Is there something I need to do to initiate the connection?