My router stopped working so I started using a regular switch to plug my RC phone into the modem. It now has a DHCP Failed error and "time/date out of sync" message. Along with the fact that it simply isn't working. No dial tone etc. I've power cycled everything multiple times. Power cycled the phone 3 times in a row. At this point I'm not sure what needs to be done.
Does the modem provide DHCP? Sounds like no IP address is getting assigned. What happens if you plug the phone directly into the modem? Note that most Polycom phones have a 2-port switch built in, so you could go from modem to phone, then from phone to PC or second device.
I'm not sure on the DHCP? Technically the phone is plugged directly into the modem via the switch, correct? A switch doesn't have a separate IP right? Right now I got cable modem>switch>polycom phone (reason being is I have 3 other devices running thru the switch and the modem only has one outbound ethernet line.
Depends on the switch setup but typically, yes. The point is, something needs to assign an IP address to the phone and it's requesting it but not getting an address back. Either the modem is not configured for that or the switch is not passing the request (or the response) along.
A lot of modems are modem/router combinations. The modem brings the service in, the router handles all communication on the network and hands out the IP addresses. Your modem doesn't have the router function built-in, and will not handle IP addresses or your network traffic. Some computers are designed to work with this type of connection, which is why it may have been working for you. You will need a new router, or a modem/router combo.