Fax – Fax To Email – Blog

Did you sometimes encounter calling a number and get a “busy” signal in exchange? Of course that happens when the person that you are calling is already talking with another (third) person. The same can happen with faxing – the regular fax lines allow you to receive only one document at a time. When somebody wants to send to you a fax while you are already receiving one, then he will get the usual busy signal. This is completely normal because the fax machine cannot print two documents at the same time and also one phone line cannot receive two calls simultaneously.

There are many companies who deal with lots of faxes every day. The number of busy tones will increase proportionally to the increasing of the incoming fax volume. The obvious solution to that problem is to add second, third, etc fax lines with corresponding machines. Of course this is not very comfortable for the users and it is very expensive to maintain – you will have many fax numbers and many machines. Can we do something else to solve this situation?

The UnityFax “Multi Line” feature comes to the rescue from the busy signals! It allows you to receive multiple faxes simultaneously and keeping only one fax number. When it is enabled the “Multi Line” will map a second phone line to the existing number. If the fax number is already receiving a fax on the first line and a second call is received, then it will be forwarded to the second incoming line. That way both faxes will be processed by the fax server and will be sent to your e-mail address in PDF or image format. This is something that is not possible with the normal fax machines!

That’s not all – UnityFax provides not just one, but up to five (5+) additional lines! That means that the service can suit the needs of even the most high pressured fax numbers. For example when you are running an attractive promotional campaign this may make your fax line “hot” and many times “not responding” (busy) to the potential inquiries. Using the UnityFax “Multi Line” service it is no longer an issue! You will not let your customers get a busy tone when sending a fax letter to you!

The final question is: how to add the additional lines to your fax number? This is done through the UnityFax Administrative Control Panel. Just login to the “Manage account(s)” area on the website, click on the link with your fax number and go to “Services” from the top menu. There you must mark the checkbox near “Multi Line” and select how many (total) lines you wish to have on this number:

The drop down menu will let you choose from two to six lines (total) for the selected account fax number. Clicking on the “Update account services” button at the bottom of the page will make the additional lines available and active immediately. You can add additional lines to every fax number that you have in the account separately. Enjoy!

Let’s continue our fax machine invention article. Now we will take a look at fax standards. The first time fax data transmission attempted unification was in 1966 by Electionic Industries Alliance (EIA) with the so called “Group 1″ standard. It is used only for analog lines and it was the first step of making compatibility between fax machines from different manufacturers. In these days the speed was not very high. It was taking between 4 and 6 minutes to transmit a single fax page! The resolution was 96 vertical scan lines per inch. The standard scan speed of the “Group 1″ machines was 180 lines per minute. The frequency of the signal was between 1300Hz (white color) up to 1900Hz (black color).

The biggest manufacturers in the USA did not comply well with the “Group 1″ standard inthe beginning. Some of them even used different schemes for modulation of the signal. That way the transmission of fax data between USA and the rest of the world (where the standard was adopted better at this time) was practically impossible. The “Group 1″ fax standard is now outdated and these machines have not been manufactured for some time.

In 1978 the international organization “Comite Consultatif International de Telegraphique et Telephonique” (CCITT), which is now known as ITU, defined the “Group 2″ standard which was immediately adopted by all fax machine manufacturers. The analog transmission speed was doubled at almost the same resolution as “Group 1″ – 100 scan lines per inch. These machines were used for a long time, however in the last two decades their usage is decreasing significantly since the digital phone lines are actively replacing analog ones.

The modern fax machines era came with the ITU-T Recommendation T.4 in 1980 with the digital phone line standard called “Group 3″. The speed of transmission can be from 9600 up to 33600 bits per second with which the required time for transmission of one fax page is decreased significantly. There are different variants available for resolutions; however most of the fax machines are using two settings:

• Standard mode: 203×98 dots per inch;
• Fine mode: 209×196 dots per inch.

There is also a “superfine” or “ultrafine” mode available on some machines.  Most of the fax machines today use the “Group 3″ standard and usually use the fine mode as default resolution.

The “Group 4″ standard came in 1984. This standard is primarily designed for digital ISDN lines but today it is also very popular for VoIP lines. It provides capabilities for much higher transfer rate of up to 64 kilobits per second. In “Group 4″ the available resolutions can be higher – up to 400×600 dots per inch (this is comparable to the quality of regular printers). If a “Group 4″ machine transmits to a “Group 3″ machine (or vice versa), the “Group 4″ machine will “fall back” to a “Group 3 compatibility mode” and of course both the resolution and the transfer rate will be lower.

How are the different fax machines “understanding” each other? During the fax-modem “handshake” (this happens before the transmission of the actual fax letter) the fax machines are exchanging information between each other. First they tell exchange information about the standards that they are following. If one of the machines is using a higher Group standard, it should be able to “fall” to “compatibility mode” in order to conform with the machine which is using the older (lower) standard. After that the machines must define what transfer rate will be used. The rule is that they will use “the highest transfer rate of the slower machine”. That way the transfer rate will be the maximum possible in which both machines can work properly. If there are some issues (like distorted phone signal or low bandwidth, the connection may fail to continue properly. If that happens the sender or the recipient of the fax letter should retry with lowering the transfer rate of the fax machine. That way he will simulate a slower machine and this will give more time for the machines to “clear” the distortions from the phone signal.

For “Group 3″ machines today the speed shouldn’t be slower than 14400 bits per second. Since the v34bis protocol modems are the most popular today, usually the transfer rate is always at the maximum of 33600 bits per second. It should be lowered manually on one of the negotiating machines only if there are issues with the phone line. The same applies for “Group 4″ machines which suffer from insufficient bandwidth.

With the Internet era many alternative variants started to be available like the “Fax over IP” for example. Probably the most popular method for transmitting faxes today is the “Internet fax” and the “fax to e-mail” services in particular. The Internet fax services are fully compatible with the Group 2, 3 and 4 standards; however the faxes are transmitted through a single server with many lines and fax modems in rack and that way the users do not have to buy and maintain the expensive fax machine and dedicated phone/ISDN line. To use a “fax to e-mail” service all you need to have is an Internet connection and an e-mail account. Additional comfor is obtained by knowing that no paper is used – all messages are transferred electronically. That way the user has an option to choose which of the received fax letters are important and which are not and they can print “hard copies” only for the documents they need. Therefore the Internet faxing is much more “environment friendly” than regular fax machines.

References:
Some information is rephrased from the Wikipedia “Fax article”