MFJ Telepatch II, Instruction Manual

VU Meter 

The VU meter is used to calibrate the amplitude of the signal you are putting into the phone line.  The 
MFJ-624DM meter is calibrated to –10 dBm.  This means that if the meter reads 100% (zero VU), it is 
actually –10dBm.  The VU meter reads the level of the telephone line.  Factory adjustment was done 
according to ta 600 ohm standard signal (0 dBm).  Telephone impedances vary in the U.S. anywhere 
from 300 ohms to 900 ohms.  Therefore, the meter readings will vary slightly from one phone system to 
another. 

Adjust the Receiver Gain control until the meter reads somewhere around 0 VU (100%) on voice peaks. 

Note:  Telephone company regulations prohibit you from putting any signal into 
the phone line with a higher level than –9dBm.  Normally, no more than –15 to –
10 dBm is necessary for good volume.

Technical Assistance

If you have any problem with this unit first check the appropriate section of this manual. If the manual 
does not reference your problem or your problem is not solved by reading the manual, you may call 

MFJ Technical Service

 at 

662-323-0549

 or the 

MFJ Factory

 at 

662-323-5869

.  You will be best helped 

if you have your unit, manual and all information on your station handy so you can answer any 
questions the technicians may ask.  You can also send questions by mail to MFJ Enterprises, INC., 300 
Industrial Park Road, Starkville, MS 39759; by Facsimile (FAX) to 662-323-6551; or by email to 
techinfo@mfjenterprises.com.  Send a complete description of your problem, an explanation of exactly 
how you are using your unit, and a complete description of your station.