Brother MFC-J3940DW User Manual

Home > Troubleshooting > If You Are Having Difficulty with Your Machine > Telephone and Fax
Problems > Telephone Line Interference/VoIP
Telephone Line Interference/VoIP
If you are having problems sending or receiving a fax due to possible interference on the telephone line or if you
are using a VoIP system, we recommend changing the modem speed to minimise errors in fax operations.
1. Press [Settings] > [All Settings] > [Initial Setup] > [Compatibility].
2. Press the option you want.
• [Basic(for VoIP)] reduces the modem speed to 9,600 bps and turns off colour fax receiving and
Error Correction Mode (ECM), except for colour fax-sending. Unless interference is a recurring problem
on your telephone line, you may prefer to use it only when needed.
To improve compatibility with most VoIP services, Brother recommends changing the compatibility setting
to [Basic(for VoIP)].
• [Normal] sets the modem speed at 14,400 bps.
• [High] sets the modem speed at 33,600 bps.
3. Press .
• VoIP (Voice over IP) is a type of phone system that uses an Internet connection, rather than a traditional
phone line.
• Brother does not recommend the use of a VoIP line. VoIP limitations in general can cause some
functions of the fax machine not to work correctly.
Related Information
• Telephone and Fax Problems
Related Topics:
• Voice Over Internet Protocol (VoIP/Telephone Line Interference)
• Error and Maintenance Messages
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Brother MFC-J3940DW Specifications

General

Card reader integrated	No
Sound power level (printing)	65.4 dB
Sound pressure level (printing)	50 dB
Scan to	E-mail, E-mail Server, FTP, File, Image, OCR, USB
Scan drivers	SANE, TWAIN, WIA
Scanner type	ADF scanner
Duplex scanning	Yes
Grayscale levels	256
Input color depth	48 bit
Output color depth	24 bit
Input grayscale depth	16 bit
Output grayscale depth	8 bit
Maximum scan resolution	19200 x 19200 DPI
Optical scanning resolution	1200 x 2400 DPI
N-up printing	2, 4, 9, 16
Print technology	Inkjet
Maximum resolution	4800 x 1200 DPI
Duplex printing mode	Auto/Manual
Print speed (ISO/IEC 24734) mono	28 ipm
Print speed (ISO/IEC 24734) color	21 ipm
Time to first page (black, normal)	4.4 s
Time to first page (color, normal)	4.6 s
Print speed (black, normal quality, A4/US Letter)	- ppm
Display	LCD
Control type	Buttons, Touch
Product color	Gray
Display diagonal	3.5 \
Market positioning	Home & office
Wi-Fi standards	802.11a, 802.11b, 802.11g, Wi-Fi 4 (802.11n)
Cabling technology	10/100Base-T(X)
Security algorithms	802.1x RADIUS, APOP, SMTP-AUTH, SNMPv3, SSL/TLS
Ethernet LAN data rates	10, 100 Mbit/s
Mobile printing technologies	Apple AirPrint, Brother iPrint & Scan, Google Cloud Print, Mopria Print Service
Printing colors	Black, Cyan, Magenta, Yellow
Duplex functions	Copy, Fax, Print, Scan
Maximum duty cycle	- pages per month
Number of print cartridges	4
Copier resize	25 - 400 %
Maximum copy resolution	600 x 600 DPI
Maximum number of copies	999 copies
N-in-1 copy function (N=)	2, 4
Time to first copy (black, normal)	5 s
Time to first copy (color, normal)	6 s
Package depth	561 mm
Package width	681 mm
Package height	493 mm
Package weight	26600 g
Quantity per pack	1 pc(s)
Paper input type	Paper tray
Total input capacity	650 sheets
Paper tray 1 input capacity	250 sheets
Multi-Purpose tray input capacity	100 sheets
Auto document feeder (ADF) input capacity	50 sheets
Cables included	Phone
Faxing	Color faxing
Fax memory	150 pages
Modem speed	33.6 Kbit/s
Fax forwarding to	E-mail, Fax, PC
Fax speed dialing (max numbers)	150
AC input voltage	220 - 240 V
Power consumption (off)	0.03 W
Power consumption (sleep)	0.9 W
Power consumption (copying)	29 W
Power consumption (standby)	6 W
Envelopes sizes	Com-10, DL, Monarch
Photo paper sizes	9x13, 10x15, 13x18 cm
Custom media width	105 - 297 mm
Custom media length	148 - 431.8 mm
Paper tray media types	Coated paper, Envelopes, Glossy paper, Photo paper, Plain paper, Recycled paper
ISO A-series sizes (A0...A9)	A3, A4, A5, A6
Maximum ISO A-series paper size	A3
Multi-Purpose Tray media weight	64 - 220 g/m²
Auto Document Feeder (ADF) media weight	64 - 120 g/m²
Mac operating systems supported	Mac OS X 10.14 Mojave, Mac OS X 10.15 Catalina, Mac OS X 10.15.3 Catalina, Mac OS X 10.9 Mavericks, Mac OS X 11.0 Big Sur
Other operating systems supported	ChromeOS
Server operating systems supported	Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2
Windows operating systems supported	Windows 10, Windows 7, Windows 8, Windows 8.1

Weight and Dimensions

Depth	477 mm
Width	576 mm
Height	375 mm