When answering mode is on I do not want to hear the ringing(4x) tones before going to answering.I've switched off the 'call screen' option. still I hear the ringing although not recording at least.

Kindly follow the steps listed below to do so:

1. Go to Apps through Home screen.
2. Tap Messaging.
3. Tap the Menu key.
4. On pop up menu select Settings.
5. Scroll to Notification settings section then tap Message alert repetition.
6. Here you can see three options available on pop up menu. They are:
   • Once: Choose this option if you want your phone ring the tone just once when receiving an incoming messages.
   • Every 2 minutes: Choose this option if you want your phone ring the tone every 2 minutes until you open the message.
   • every 10 minutes: Choose this option if you want your phone ring the tone every 10 minutes until you open the message.
7. Tap the required message alert repetition option you wish to use. When the dot indicator next to the option shows green means the option is selected.
8. Tap Home button to return to the standby mode.

By adjusting message alert repetition just once or more than once, now your phone will notify you when receiving new message and repeating the tone according to the settings you've just done. So, what's the option you use on your phone?

I'm going out on a limb here, and guessing it's a Canon imageClass MF4150... If not, please disregard this solution.

The advanced manual can be viewed / downloaded / printed here, directly from Canon:

http://gdlp01.c-wss.com/gds/0900006459/imageCLASS_MF4150_Advanced_Guide_EN.pdf

To stop it from interfering with the telephone conversation:

Issue: Fax interrupts telephone conversations in answering machine mode (AnsMode)
Solution: Setting the Receive Mode - ICMF 4150

Setting the Receive Mode

1. Press <Additional Functions>.
   
   
   
2. Use <> or <> to select [5 FAX SETTINGS], then press <OK>.
   
   
   
3. Use <> or <> to select [3 RX SETTINGS], then press <OK>.
   
   
   
4. Use <> or <> to select [3 RX MODE], then press <OK>.
   
   
   
5. Use <> or <> to select the desired receive mode, then press <OK>.
   - For [AnsMode], make sure an answering machine is connected to the machine.
   If [AnsMode], [FAX/TEL], or [DRPD] is selected, you can select some settings as below:
   
   [AnsMode]
   --- [AnsMode CHK TIME] (select time from 10 to 30 seconds for the answering machine to start playing outgoing message after receiving a call)
   --- [FAX DETECT TIME] (select the duration from 10 to 70 seconds for the fax to detect)
   
   [FAX/TEL]
   --- [RING START TIME] (select the time from 0 to 30 seconds for the phone to start ringing after receiving a call)
   --- [F/T RING TIME] (select the duration of ringing from 10 to 45 seconds)
   --- [F/T SWITCH ACTION] (select the action the machine will take after the ringing ends, Receive or Disconnect)
   
   [DRPD]
   --- [NORMAL RING]
   --- [DOUBLE RING]
   --- [SHORT-SHORT-LONG]
   --- [SHORT-LONG-SHORT]
   --- [OTHER RING TYPE]
   
6. Press <Stop/Reset> to return to the standby display.

Go to menu option and choose the option fax and set the parameter like auto receive or manual set the ring auto answer mode after certain ring. If it is in auto receiving mode it will receive the fax after the ring which you set. Make sure the phone wire which you insert in fax machine getting proper dial tone and getting out going calling facility.
Have a nice day and do not forget to rate please...!

Step by step information at the link below.
Brother Fax T96
The F/T Mode is used to allow the fax machine and the telephones to share the same telephone line. When a call comes in, the fax machine and all extension telephones on that line will ring according to the number of rings you have set for the Ring Delay.
When the Ring Delay is completed, the fax machine will answer the call and determine if it is a fax call or a telephone (voice) call.
The fax machine can determine this by the signal it is receiving on the telephone line. If someone is sending a fax automatically , the sending fax machine will transmit a fax tone (a series of beeps every 3 seconds).
If your fax machine hears these tones, it will receive the fax.

If the fax machine does not hear any fax tones, it assumes it is a telephone (voice) call and will begin ringing the F/T ring tones (double ring) for the length of time you selected for the F/T Ring Time. These tones will only ring on the fax machine's handset (extension or external phones will not ring). At the end of the F/T ring time the fax machine will go into the receive mode in order to receive a manual fax.
(If the call was a voice call and was not answered, the caller will hear the fax receive tones also).

• If you answer the call before the fax machine(during the ring delay period) and determine it is a fax, you can transfer the fax to the fax machine for receiving.
  
  
• If you answer the call on an "extension" phone and hear a beep every 3 seconds (automatic fax) or silence (manual fax), press *51 or *91 for New Zealand (remote activation code) on the telephone keypad, wait to hear the fax machine turn on (chirping sounds) and then hang up.
  
  
• If you answer on the handset of the fax machine and hear a beep every 3 seconds or silence, press the Fax Start or Start/Copy key on the control panel of the fax machine and then hang up the handset.
  
  
• If you answer a call on an "extension" phone during the F/T Ring Time, you will hear the F/T ring tones.
  To release the call from the fax machine, press #51 or #91 for New Zealand (remote deactivation code) on the telephone keypad and you can speak to the calling party.
  
  
• If you pick up the handset of the fax machine during the F/T ring time, you may talk to the calling party immediately.

Go to menu option and choose the option fax and set the parameter like auto receive or manual set the ring auto answer mode after certain ring. If it is in auto receiving mode it will receive the fax after the ring which you set. Make sure the phone wire which you insert in fax machine getting proper dial tone and getting out going calling facility.
Have a nice day and do not forget to rate please...!

Firstly, you will need to get a 2nd ringtone from your phone provider. Most of them will provide a designated "fax ring" (not a new number) for little or no cost.

In DRPD mode, you can receive a call using the Distinctive Ring Pattern Detection (DRPD) feature. “Distinctive Ring” is a telephone company service which enables a user to use a single telephone line to answer several different services.

Using the Distinctive Ring Pattern Detection feature, your fax machine can “learn” the ring pattern you designate to be answered by the fax machine. Unless you change it, this ringing pattern will continue to be recognized and answered as a fax call, and all other ringing patterns will be forwarded to the
extension telephone or answering machine plugged into the EXT. jack. You can easily suspend or change Distinctive Ring
Pattern Detection at any time.

Before using the Distinctive Ring Pattern Detection option, Distinctive Ring service must be installed on your telephone line by the telephone company. To set up Distinctive Ring Pattern Detection, you will need access to another telephone or someone available to dial your fax number from outside (a cell phone will do!).

To set up the DRPD mode:

1 Press Menu until “Fax Setup” appears on the top line of the display.
2 Press the scroll button ( or ) until you see “Receive Mode” on the bottom line and press Enter.
3 Press the scroll button ( or ) until you see “DRPD Mode” on the bottom line and press Enter.
4 When “Set” displays on the bottom line, press Enter.
“Waiting Ring” appears on the display.
5 Call your fax number from another telephone. It is not necessary to place the call from a fax machine.
6 When your machine begins to ring, do not answer the call.
The machine requires several rings to learn the pattern.
When the machine completes learning, the LCD displays “End DRPD Setup”.
If the DRPD setup fails, “DRPD Ring Error” appears. Press Enter when “DRPD Mode” displays and retry from step 3.
7 To return to Standby mode, press Stop/Clear.
When the DRPD feature is set up, the DRPD option is available in the Receive Mode menu.

To receive faxes in the DRPD mode,
you need to set the menu to DRPD;

NOTES:
• DRPD must be set up again if you re-assign your fax number, or connect the machine to another telephone line.

• After DRPD has been set up, call your fax number again to verify that the machine answers with a fax tone. Then have
a call placed to a different number assigned to that same line to be sure the call is forwarded to the extension telephone or answering machine plugged into the EXT. jack.

• In Tel mode, you can receive a fax by picking up the handset of the extension phone and then pressing the remote receive code Alternatively, you can press On Hook
Dial (you can hear a fax tone from the remote machine) and then press Start on the control panel of your machine.
• In the Fax mode, the machine answers an
incoming call and immediately goes into fax
reception mode.
• In Ans/Fax mode, the answering machine answers an incoming call, and the caller can leave a message on the answering machine. If the fax machine senses a fax tone on the line, the call automatically switches to Fax mode.
• In DRPD mode, you can receive a call using the Distinctive Ring Pattern Detection (DRPD) feature. This option is available only when you set up the DRPD Mode.

The full user manual for your machine is located here

Hope that is of help to you :)

flash the phone with jaf using latest flash files for rh 305

turn up the volume with the ringtone volume controler while on a call

Press the 'RECEIVE MODE' button on the right side of the control panel, its next to the large 'FAX START' button. Here are your options :

Select Receive Mode
MANUAL
—You must answer all calls yourself. If you hear fax tones, press
Fax Start
to begin receiving the fax, then hang up. You can use this mode with
Distinctive Ringing. (See
Distinctive Ring
, page 8-1.)
FAX ONLY
—The fax machine automatically answers every call as a fax call. You
cannot receive a voice call, but you can dial out and make a voice call.
FAX/TEL
—The fax machine automatically answers every call. If the call is a fax, it
prints the fax. If the call is not a fax, it signals you with a double-ring (ring-ring),
different from the phone company ringing, to alert you to pick up the call. If you select
this setting, you’ll need to set the Ring Delay and F/T Ring Time features (on the
following pages). If you have extension phones on the same line as the fax machine,
set Ring Delay to 4. (See
For FAX/TEL Mode Only
, page 5-5.)
TAD:ANSWER MACH.
—This is the only setting in which you can use an external
answering machine. Your telephone answering device is connected to your fax
machine, and answers every call. Once the TAD answers, the fax machine listens for
fax tones. If it detects fax tones, it prints the fax.
The TAD setting works
only
with an external telephone answering device (TAD); it
does not work with telephone company Voice Mail. Ring Delay and F/T Ring Time
do
not
work in this setting.

TAD is Telephone Answering Device. TAD mode is the only mode that can be used with an external telephone answering device (unless you are using a distinctive ring number for receiving faxes). Your telephone answering device must be connected to the jack on the fax machine (labeled "EXT" for USA). When someone dials your telephone/fax number (to send a fax or to speak to you), all the telephones (including the FAX) will ring according to the number of rings you set on the TAD. The Ring Delay setting is not recognized in the TAD mode. If you do not answer the call, the TAD will answer. As your outgoing message is playing, the Fax is in the background, silently listening for fax tones. If the FAX hears fax tones, it will automatically go into the receive mode. If the FAX does not hear fax tones, it remains silent, allowing the caller to leave a message. The above information is correct for a Brother fax machine. Is your fax automatically picking up the call or do you have to push a panel button to start the receive fax process? Perhaps the fax is already "in" your fax machine's memory and only needs a manual printout. Check the fax call log.