Modems and routers are functionally totally different.
A modem converts between the multi-frequency analogue signals used on the connection between an ISP and their customer and the digital signals used by routers.
The basic function of a router is to provide a path between two or more different networks. A home router normally support two networks – the private internal network and the Internet connection.
Home routers tend to include additional functions:
1) A switch that allows the private network to be made available on multiple Ethernet ports and, for a wireless router, on a WiFi network.
2) A firewall that protects the router and the private network from attacks from the Internet.
3) For a wireless router, one or more WiFi networks.
4) Network/Port Address Translation mechanisms that allow multiple devices on the private network to share a single IP address on the Internet.
Some routers include an integrated modem so there is no need for a separate modem box. Some routers also have a number of other features to control bandwidth, block unwanted devices from connecting, offering 'guest' access to the Internet but excluding possible connection to devices on the private network, etc.
You cannot connect more that one modem to an ISP line, or more than one device (router or single computer) to a true modem.
You can interconnect routers either to provide a single large network across two or more routers, or to provide separate subnets that have various degrees of isolation between them. All routers can be connected to provide a single larger subnet subject to their offering support to three or more devices, and normally with at least two PC/LAN Ethernet ports plus WiFi (or three or more Ethernet ports without WiFi). For isolated subnets, the secondary router(s) must have Ethernet WAN/Internet ports.
Unfortunately you forgot to include any makes or model numbers of the modems that you have, so nobody can look up the actual specifications to see just what is possible.
I hope this helps.
Good answers so far, but what you're calling a modem, may in fact, be a gateway device (combo modem + router) or a router. Just to be sure, tell us the makes & models of your modems. (Ex: Motorola SB1234)
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1 modem 1 connection you can not us the second modem
Nope, you don't have access to the WAN port to connect to anything. On top of that, you don't want 2 routers on your network, double nat'ing is always a bad idea.You just need a switch.