A Cable Modem question:

[RC]

A friend recently dropped her local phone company DSL for cable internet. The cable modem they gave her has a telephone connection and she was told it needs to be hooked up for the modem to work properly. On a two way cable connection, why does it need a telephone connection? Isn't this roughly the equivalent of having to plug your cell phone into your land line for the cell phone to work?

google didn't come up with much on this.

I'm a few blocks away and my cable internet has worked just fine for years with any need or place for a telephone connection.

So what's up with the phone connection on a cabel modem?

[IDemo]

1. That's an outdated technology

I found the following on a Google search:

All of the cable modems attached to a cable TV company coaxial cable line communicate with a Cable Modem Termination System (CMTS) at the local cable TV company office. All cable modems can receive from and send signals only to the CMTS, but not to other cable modems on the line. Some services have the upstream signals returned by telephone rather than cable, in which case the cable modem is known as a telco-return cable modem.
http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci211726,00.html

and --

CDLP was a proprietary system that was made by Motorola. CDLP CPE was capable of both PSTN (telephone network) and RF (cable network) return paths. The PSTN return path cable modem service was considered 'one way cable' and had many of the same drawbacks as satellite Internet service, and as a result it quickly gave way to two way cable. Cable modems that used the RF cable network for the return path were considered 'two way cable', and were better able to compete with DSL which was bidirectional. The standard is more or less defunct now with new providers using, and existing providers having changed over to, the DOCSIS standard.
http://en.wikipedia.org/wiki/Cable_modem

It sounds as if your friend could do better with another provider. I'm using Clearwire, a wireless service, and highly recommend it (or a similar company, if available).

[RC]

2. She just had it installed a few days ago.

I'm thinking a visit with a cable rep is in order here.
There are no filters involved and the phone work normally.

There is not much real choice here. Cable, DSL or wireless, in descending order of speed.

[RoyGBiv]

3. What IDemo said ...

Satellite Internet providers still use those, but I didn't know any cable company still did.

What company is this, if you don't mind me asking?

[RC]

4. Cableone

[RoyGBiv]

5. Huh ...

Cableone is a company that goes into areas that big providers don't want to mess with, and they usually work by purchasing infrastructure originally built by someone else and not doing much with it afterward other than maintain it. That might explain things except that you seem to be on the same system and use the more common DOCSIS standard.

Now, having said that, the emerging technology when I left the industry was a type of modem that, without getting into the technical details, served as both a cable modem and a VOIP modem for the cable provider's phone service. It would have a phone outlet on it, but that would be for the phone service itself, not the Internet service.

Did your friend happen to get phone service with the cable company also? Or, could it be one of these newer types of modems and somehow a mistranslation of the instructions occurred?

If not, I'm at a loss.

[RC]

6. Ah ha, a Clue! Duh!

She did switch her phone service also. Now it makes sense. :blush:
Thanks.