Faxing need instructions for setup for faxing using one phone line setting up fax only and changing back to phone my product is a brother intellifax 1840c

Brother's support page for this model is here. You can find the manual, drivers and other information there.

This is basically a stand-alone fax machine which can be used with a computer for some functions, so there may not be anything you need to install. If you just want to use this as a fax machine, you only need to connect it to your phone line and go through the basic setup (phone number, operating mode, etc.). It's all done through the built-in display and keyboard.

If you want to use this with your computer, it's the same process as installing any printer. Download the appropriate drivers for your operating system and run the installation program, plug in the connecting cable and it's installed.

Yes. Use a splitter. If fax has fax switch built in then fax calls should go to fax only and not phone. A fax switch can be fitted separately.

Your machine did not recognize the new cartridge. Remove the yellow, count to 10 then replace it. The machine will ask "did you change the color yellow?" Select yes by dialing "1" - if after the cleaning cycle "near empty" still appears, you need to contact Brother for repairs. You can safely use the machine until "INK EMPTY" appears.

IS THE PHONE LINE PLUGGED IN TO THE RIGHJT JACK YOU WILL NEED TO CHECK THIS OUT FIRST GOOD LUCK BROTHER TECH

Plug the fax phone cord into the LINE port of the machine. The rest is automatic.

It should automatically default to AUTO RECEIVE. Plug the phone cord into the LINE port on the machine.

Verify dial tone. Verify machine is set to "fax only" and auto - answer.

Call your cell phone from the fax machine.

Call some fax numbers on a regular phone and listen for fax tones.

Do you have a DSL phone line?

Fax machines are designed to have their own dedicated fax line.

Anything else is a **** shoot.

the supply line may be dry.

in any case hre is the maual

http://www.retrevo.com/s/brother+1840++fax+manual