Call Vonage first and see if they have an answer. Sometimes they ship new equipment to replace what you have, but, as powerpig said, it's probably your cable equipment. Call you ISP service provider and relate the problem. My sister had trouble with modem and once new one installed.. Vonage is crystal clear and no problems whatsoever.

I don't have Vonage or local Time Warner's equivalent nor do I plan to get it, but my sister's Vonage performs flawlessly.

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Nello Tare

1982 300D (266,001 mi.) looking and running great

Previously owned:
1976 450 SLC
1983 300D
1976 300D
also
1982 Jaguar XJ6 (loved, but gone)