Spectrum (formerly Time Warner Cable) uses various cable modems to connect their customers to their internet services.
- Arris DG1670
- Netgear CM500
- Netgear CM600
- Netgear CM1000
- Arris SURFBoard SB8200
- Netgear CM700
- All SURFBoard modems except the SB8200
- Disable IPv6
- Disable entire Firewall
- Disable SIP ALG
I have a "bad" modem, what can I do?
Call Spectrum and tell them your existing modem is not sufficient for VoIP, and you require the Arris DG1670 to be installed. If they ask for details, tell them the existing modem is causing VoIP packet loss, and the Arris is the only thing that works reliably on cable.
What makes a "bad" modem?
The bad modems listed above will introduce noise into your phone calls. They are very old modems that contain processors that can't handle the load of multiple phone calls happening at the same time. They introduce things like jitter and packet loss into the connection.
Even though these modems might work well for the normal internet connection (email, Facebook, etc.) they are not sufficient for a very sensitive system like VoIP.
Spectrum installed 2 boxes - Which one is which?
Spectrum will typically install a very small Motorola modem for their public "hotspot". This is something they offer free to their customers, and you can unplug it if you want to. The important modem is the larger one that feeds into your network.