Shared Knowledge


Voice Over IP?


5 February 2007



Summary: think twice if you have a security system that "dials" a remote station or are unwilling to invest in an uninterruptible power supply for your cable modem.






Vonage, Cox, Comcast, etc, etc, all offer voice-over-Internet-protocol (VOIP) telephone service.


Have seen their commercials for some time and with me setting on a cable modem for high speed Internet, thought recently it was time to look into it seriously. Well, why is everything so hard?


From the get go, I understood that I would have to have an uninterruptible power supply for my cable modem, router, the VOIP telephone adapter and my home’s cordless telephone answering machine and fax or else I would lose telephone service during any electrical power outage, but I did not fully understand that VOIP has or can have problems handing my:


-         FAX machine


-         Home security system


-         More than 5 telephone units plugged into wall outlets


-         Tivo


FAX: apparently some FAX machines work fine, while others do not. Problem is that the analog signal coming from a FAX must be converted to digital for transmission for VOIP and errors can occur in conversion even with VOIP protocol settings adjusted for wider bandwidth or whatever. Now I don’t FAX a lot but when I want to do it, I want to do it.


Home security system: I have an old AT&T home security system that actually dials the number of a security monitoring company at every home intrusion or smoke detection. In this case, apparently the analog to digital conversion problem can occur with some errors distorting the message actually sent to the monitoring station. It is clear from the VOIP web sites that they do not recommend home security systems be attached.


Limitation on number of phone jacks. I put off even thinking about VOIP as I was under the impression that its service would be to only one phone. Upon investigation, it is now clear that I could simply unhook my telephone service from the local telephone company at the box on the outside of the house and then run the output of the VOIP adapter to a phone jack and have telephone service on all jacks in my house. Easy! Except that VOIP Web sites say that “driving” more than 5 telephones is not recommended as the ringers might not work on all units. Well, this is not a big problem for me as I have a cordless phone arrangement in my house where only one actual phone jack connection supports 7 different cordless phones but I do have TIVO, security system monitoring and several caller ID boxes sitting around, which brings my total to close to 5 and as always, I never like being limited by anything. Who knows the future and what we might need tomorrow? Who would have predicted the need for phone jack for Tivo?


Tivo: Tivo uses a phone line to get software updates and to also download program schedules, 2 weeks at a time. As with other devices, TIVO was built to use its internal modem and does not like the analog to digital conversion VOIP requires, uses.


Apparently from reading web sites related to my home security system, VOIP and Tivo, all recommend that a regular telephone line be kept to support these devices. Regular telephone line? Wasn’t that the point of getting VOIP to begin with: getting rid of the current telephone line and associated charges?


Upon due consideration, although I would love to have VOIP from an engineer, geek, point of view and I am pretty sure I could resolve all problems with all my various telephone-based devices, I just can not justify the hassle for VOIP small cost savings.


Now, don't get me wrong. If you want to just have telephone service and do not have a FAX, security system or a Tivo, VOIP might just be for you, especially if you want to make a ton of long distance calls. You decide.




Ron - Shared Knowledge Home