Redial When sending a document, if the line is busy the fax does not automatically redial. It used to redial 3x then the fax would fail. Any ideas?

make sure your connected in the right plug one is for a hand set also see if your getting a dial tone could be bad line if that checks ok then replace lcu pcb

How to enter Fax mode
Before sending faxes, make sure (Fax) is illuminated in
green. If not, press (Fax) to enter Fax mode. The default
setting is Fax.
How to dial
You can dial in any of the following different ways.
Manual dialing
Press all of the digits of the phone or fax number.
Setup Send
3 - 2 SETUP SEND
Speed-Dialing
Press Search/Speed Dial, #, and then the two digit Speed-Dial
number. (See Storing Speed-Dial numbers on page 5-1.)
Search
You can search for names you have stored in the Speed-Dial
memories. Press Search/Speed Dial and the navigation keys to
search. (See Storing Speed-Dial numbers on page 5-1.)
* To search alphabetically, you can use the dial pad to enter the first
letter of the name you are looking for.
Fax Redial
If you are sending a fax manually and the line is busy, press
Redial/Pause, and then press Black Start or Color Start to try
again. If you want to make a second call to the last number dialed,
you can save time by pressing Redial/Pause and Black Start or
Color Start.
Redial/Pause only works if you dialed from the control panel.
If you are sending a fax automatically and the line is busy, the MFC
will automatically redial one time after five minutes.
If the LCD shows Not Registered when you enter the
Speed-Dial number, a number has not been stored for it.

Color fax transmission
Your MFC can send a color fax to machines that support this feature.
However, color faxes cannot be stored in the memory. When you
send a color fax, the MFC will send it in real time (even if Real Time
TX is set to Off).

This section describes dialing and sending faxes directly using the Numeric buttons.

note:

• A PBX (Private Branch Exchange) is an on-site telephone switchboard. If your machine is connected through a PBX or other telephone switching systems, you have to dial the outside line access number first, and then the number of the party you are calling.
  

Sending a Fax with the Numeric Buttons .

Click here for other useful sending methods.


1. Preparing for sending a fax.(1) Make sure that the power is turned on.

(2) Load a document on the Platen Glass or in the ADF.

important:

• When sending a double-sided document, set the document on the Platen Glass. You cannot scan double-sided documents from the ADF.

(3) Press the FAX button.
The fax standby screen will appear.

(4) Adjust the density (scan contrast) or image quality (fax resolution) as necessary.
See "Adjusting the Sending Quality"

2. Sending the fax.

• When the document was loaded on the Platen Glass:

(1) Use the Numeric buttons to dial the recipient's number.

(2) Press the Color button for color sending, or the Black button for black & white sending.
important:

• Color sending requires that the recipient's fax machine supports color faxing.

(3) Press the OK button.
The machine starts sending the fax.
note: When loading two or more documents

• Load the next page, and press the same button as you pressed in (2) of step 2. Repeat the same procedure to scan all pages of the document, and press the OK button.
  
• When you have sent the first page with the Black button, the following pages will be sent in black and white.

When the document was loaded in the ADF:

(1) Use the Numeric buttons to dial the recipient's number.
(2) Press the Color button for color sending, or the Black button for black & white sending.
The machine scans the document automatically and starts sending the fax.
important:

• Color sending requires that the recipient's fax machine supports color faxing.

note:

• To cancel sending a fax, press the Stop button, and follow the instructions on the LCD.
  
  
• If documents remain in the ADF after pressing the Stop button during scanning, "Close the feeder cover [OK]Eject the document" will appear on the LCD. Press the OK button so that the remaining document is automatically fed out.

Automatic redialing

• When sending a fax and the recipient's line is busy, the machine will redial the number after a specified interval. Auto redial is enabled by default. Auto redial can be enabled or disabled by selecting ON or OFF. Select ON to specify the number of redialing in Redial times and redialing interval in Redial interval.

Redialing the Number Dialed with the Numeric Buttons

1.Prepare for sending a fax.
(1) Make sure that the power is turned on.
(2) Load a document on the Platen Glass or in the ADF.
(3) Press the FAX button.
The fax standby screen will appear.
(4) Adjust the image density (scan contrast) or quality (fax resolution) as necessary.
See "Adjusting the Sending Quality"
2. Select the telephone number recently dialed.
(1) Press the Redial/Pause button.
Most recently dialed fax number using the Numeric buttons will appear.
(2) Use the (-) or (+) button to select the number to redial.

(3) Press the OK button.
The selected number will appear in the fax standby screen.
3. Send the fax.
Press the Color button for color sending, or the Black button for black & white sending.
important:

• Color sending requires that the recipient's fax machine supports color faxing.

Load an original in the automatic document feeder (ADF)
You can copy, scan, or fax a single or multiple-page A4, letter, or legal-size document by
placing it in the document feeder tray.
The document feeder tray holds a maximum of 20 sheets of letter or A4-size paper or 15
sheets of legal-size paper.
To send a basic fax from the control panel
1. Load your originals. For additional information, see Load originals.
2. Enter the fax number by using the keypad, press Speed Dial or a one-touch speed
dial button to select a speed dial, or press Redial/Pause to redial the last number
dialed.
TIP: To add a pause in the fax number you are entering, press Redial/Pause,
or press the Symbols (*) button repeatedly, until a dash (-) appears on the display.
3. Press START FAX Black.
If the device detects an original loaded in the automatic document feeder, it
sends the document to the number you entered.
TIP: If the recipient reports issues with the quality of the fax you sent, you can
try changing the resolution or contrast of your fax.

for further refernce check out the online manual
http://h10032.www1.hp.com/ctg/Manual/c01181836.pdf

don't sent it by automatic redial dial handsfree monitor then no

If the line is busy on the other end, your machine will put it in redial state and will try again. However, the redial function will depend on the setting how many try it will make. If the setting is 2 as an example, it will redial twice only and if it is still a failure it will treat the transaction as "NO" or "NG". You can check this in the transaction list of your machine. As you said, there are numerous complaint, check if the complaint is with the same receipient, if so most probably the end machine is having some problem. If from different destination please have your machine checked by the local service provider.

is that a fax error code?
well here is the description for error 634:

Redial count over with no
response, or busy tone was not
detected.
Note:
U.S.A., and Canadian models
will redial only once if a busy
tone is not detected.

this happens when you send fax on an autofax destination.
you may also check your setting for your redial count
that's it :)

please go to this link and setup your redail time. fax will not redial if your are sending fax in manual mode.
http://www.brothersupport.com/Facsimile/ALL/UG_FAX2820_FAX2920_MFC7220_MFC7225N.pdf

I dont know how we got disconnected but here is the instructions

Adjust the width of the document guides (1)
to fit the actual size of the document.
2 Insert the document (up to 10 pages) FACE
DOWN (2) until a single beep is heard and
the unit grasps the document.
L If the document guides are not adjusted
to fit the document, re-adjust them.
3 If necessary, press {A} or {B} repeatedly to
select the desired resolution.
4 Press {DIGITAL SP-PHONE}.
5 Dial the fax number.
6 When a fax tone is heard:
Press {FAX/START}.
When the other party answers your call:
Ask them to press their start button. When
the fax tone is heard, press {FAX/START


To redial the last number
1. Press {REDIAL/PAUSE}.
2. Press {SET}.
L If the line is busy, the unit will automatically
redial the number up to 2 times.
L To cancel redialing, press {STOP}.
To send more than 10 pages at a time
Insert the first 10 pages of the document. Add
the other pages (up to 10 at a time) before the
last page feeds into the unit.
Pre-dialing a fax number
You can dial the fax number first before inserting
the document. This is convenient if you need to
refer to the document for the other party’s fax
number.
1. Enter the fax number.
2. Insert the document.
3. Press {FAX/START}.
Sending from memory (Quick scan feature)
You can scan the document into memory before
sending it. To use this feature, activate feature
#34 (page 62).
1. Insert the document.
2. Enter the fax number.
3. Press {FAX/START}.
L The document will be fed into the unit and
scanned into memory. The unit will then
transmit the data. If the document exceeds
the memory capacity, transmission will be
canceled and this feature will be turned OFF
automatically. You must transmit the entire
document manually.
L This feature cannot be used if {DIGITAL SPPHONE},
{TALK} or {SP-PHONE} is
pressed.
To stop transmission
Press {STOP}.

pleas close the redial option and other number may be busy or finished