How to make fax machine work after switched from hardline phone to a VOIP phone service?

Question

After I switched from AT&T hardline phone (PSTN) to iTalkBB Internet phone (VOIP) service, my same voice phone works just fine while my same fax machine does not. My Internet Service Provider (ISP) is Road Runner – a Time Warner Cable division. They give me a Motorola cable modem with one Ethernet port (RJ45) which I used for my D-Link router. All my two computers and two VOIP boxes, one for phone and one for fax with different phone number, are behind the router.

According to my VOIP provider’s advice, I've tried to slow down transmission speed (on fax machine) from the default 33.6 (mbps) to 9600 baud and turned off ECM. So far I can send out faxes to some numbers but not all numbers, and could not receive any fax including the very fax machine that received my fax.

My VOIP provider then suggested me to hook up the VOIP box directly to the cable modem so it has its own internet connection. I tried that by taking off the router from the cable modem and just plug in the fax VOIP box to the cable modem. It dose not work – did not even get the dial tong – either with regular patch cable or a crossover cable. Time Warner Cable told me that they do have two port cable modem but only give to me when I subscript to their digital phone (VOIP). However, their price is 8 times higher than iTalkBB ($40 vs $5 per month). I tried to find a cable modem with more than one Ethernet port. I could not find any in three major electronic stores as Best Buy, Circuit City, and Micro Center.

I am now thinking to roll back my fax line to AT&T for a basic plan cost $15+tax=$20 per month. That way I will be sure it works – it’s a hardline.

Somebody on Iinternet advised me to wait for the undergoing Fax Over Internet Protocol (FOIP). But I don’t know where this baby is – if any. On the other side of the story, somebody on Internet stated that he switched to VOIP, and his fax machine works flawlessly ever since for a year so far. My line condition is no comparison to his, but I did make some improvement – half way so far.

Is there anybody has a clue or suggestions please help me out. Many thanks!

Answer 1

Actually, you don't need a cable modem with more than 1 port to split your network up. I use a Linksys "5-Port Switch" ($40) connected to the output of my Cable Modem.



All you need is an allocation of two IP addresses from Time Warner.

Most ISP's that provide HighSpeed Internet also allow you two Dynamic IP Addresses. (You are using Dynamic IP assignment from ISP rather than Fixed IP?) In my case, I had to contact customer support and ask them to "activate" the 2nd dynamic IP (even though they say it is free, I still had to request it to be activated because most people don't know how to use two IP's).



Modem connects to Port 4 or 5 (Uplink port) of the Linksys Switch.

From the Linksys Switch:

- I have a Linksys WRT-54G NAT-Router connected to Port-1.

- I have a D-Link DI-804 connected to Port-2



Each Nat-Router connected to the Switch gets assigned its own dynamic IP. So now I have two separate local networks, each behind it's own Nat-Router.



- Behind WRT-54-G I have my PC on port-1 and Linksys PAP2T-NA VoIP ATA on port-2.

- Behind the DI-804, I have another Linksys PAP2T-NA VoIP adapter.



I have my ATA's configured for BYOD VoIP services like CallCentric and InPhonex. (And Les.net and Voip.ms as backups).



Everything is working great this way with two dynamic IPs and using a Switch to divide up the network.



You could probably do the same thing.

I believe you are using the Linksys SPA-2102 ATA?

Just be sure the ATA is set for Dynamic IP address assignment if your ISP is providing you with Dynamic IP's. Or, if they give you Fixed IP's, then your devices need to be set to those IP's.



There are two ways Fax can work over VoIP.

The ATA must be using G.711u Codec. The SPA2102 does support G.711u. This is a wide-band codec that is capable of Fax "Pass-Through", which means it should pass Fax signals ok.



There is also a Fax specific Protocol called T.38. The SPA-2102 also supports T.38.

I believe iTalkBB has preconfigured your ATA to accomadate Fax, as the claim to on their web site and say "press # key to initiate sending of Faxes". I suspect that the # key is either telling the ATA to use G.711u or T.38 Codecs.

Answer 2

8

Answer 3

Sometimes it has to do with the codec being used by your VOIP provider. G711 is the standard used by Hardlines and most VOIP over lan. G729, which some providers use, is a different algorithm and has a different capture rate so that it can use less bandwidth over WAN connections and so it captures less information..thus some fax data may be lost. You may check with your VOIP provider to see what codec you are using and if this is configurable.