Overview

Single-page fax takes (on average) approximately one minute to be transferred. This would include handshaking, negotiating, fax transmission and disconnecting. As an example, we will consider a company that needs to send 1000 faxes and receive 1000 faxes during an 8-hour working day.

Solution

Sending faxes:

Taking the average amount of time in which a fax can be transmitted as mentioned above, we can conclude that:

• 60 single-page faxes can be sent in an hour.
• 480 single-page faxes can be sent in 8 hour day.

The above is the number of faxes that can be sent on one line. Therefore in order to send all 1000 faxes within 8 hours, 2.08 fax lines are required. This assumes that the faxes are queued before sending them. If most of the 1000 faxes are sent in a short period of time more lines may be required.

Receiving faxes:

Using the same calculation, we can conclude that:

• 60 single-page faxes can be sent in an hour.
• 480 single-page faxes can be sent in 8 hour day.

However, this assumes that all faxes are being received exactly after each other. In reality, this does not occur, since you cannot queue incoming faxes, and you will be receiving multiple faxes at the same time. Because of this, you should multiply the number of lines required by 3. This will avoid that fax senders get a busy tone.

Therefore in order to receive 1000 faxes within 8 hours, 6.25 fax lines are required.

Number of lines required:

For this example, we have concluded that the company required 2.08 lines for sending and 6.25 lines receiving, which rounds the total requirement to 8 fax lines.  

The following variables will affect the speed which is used to send or receive a fax:

• Line speed
• Size of fax
• Is the line ISDN or Analog
• Speed of sending and receiving fax machines/fax cards/modems. The fax is always transmitted at the speed of the slowest device.
• Fax resolution