HP Fax Settings for VoIP

VoIP Fax Settings for the HP J3500/J3600

HP 3600 series All-in-One fax.The HP All-in-One J3500 and J3600 series fax machines have been very popular. These machine default with speeds set for Fast or v.34 33600 Baud rate. This speed is too fast for sending faxes over VoIP and would result in a communications error in most cases. Additionally, the J3500 and J3600 series machines come defaulted with ECM (Error Correction Mode) enabled. content goes here. We have listed here the easy steps to both disable ECM and lower the Baud rate to 9600bps for faxing over a VoIP connection.

The following instructions should work on most HP fax machines and 3 in 1 machines.


How to Disable ECM and Lower the BAUD rate on HP Fax Machines

Disabling ECM (Error Correction Mode) on J3500/J3600.

When disabling ECM on the HP 3500/3600 series machines the speed will be lowered to medium or v.17 or 14,400bps. Typically the medium speed setting would be too fast for VoIP even though some very stable connections might find that they will get a good transmission on occasion. The settings should be for Slow which is 9600bps which is the recommended HP speed for VoIP connections. To disable ECM:

  • Go to Setup, then select 5, then 6.
  • Choose Advanced Fax Setup and navigate to Error Correction Mode.
  • Choose Off to disable, and then hit OK.

HP Fax over VoIP tip.NOTE: The above instructions should be good for the entire HP J3500 and HP J3600 All-in-One machines. These would include HP J3500, J3508, J3520, J3600 series, etc. You will also find that many other HP fax machines will follow these same steps.


Lowering the speed to 9600bps on HP J3500/J3600.

There are three speeds on the J3500/J3600 HP All-in-One series machines. They are Fast, Medium and Slow. Slow is the preferred speed for faxing over VoIP which is 9600bps. To set your machine to 9600 do the following:

  • Enter Setup.
  • Navigate to Advanced Fax Setup and then choose Fax Speed.
  • Next choose Slow and hit OK.

HP Fax Speeds explained.NOTE: The following speeds correlate with Fast, Medium and Slow. Fast = v.34 33600, Medium = v.17 14,400, and Slow = v.29 9600.