Engeneer mode for PT410

[cactus31odo]

Hy all,
My phone is this:
http://www.******.com/Free-shipping-...66b330458.html

or

http://www.tomtop.net/Mobile-phone-PT410.html
But on the back of the phone is this:
--------------------
MERIT Model:T10
IMEI:3566.......9873
MADE BY MERIT
--------------------
I have a problem with my dual sim phone. To be exactly there is an echo present all the time when I am in a conversation. This echo is present on both networks, so the problem is in the phone it'self.
I read some where on this forum that the eco problem can be resolved if you enter in the Engeneer mode > Audio > Normal Mode > Side tone , and then set the Side tone to 0 (ZERO).
The Engeneer codes that I have found on this forum:
1. *#110*01# - don't work
2. *#3646633# - don't work

On this page
http://forum.gsmhosting.com/vbb/showthread.php?t=608868
I have found the above codes and others.

I will mention now just the codes that work on my phone:

IMEI *#06#
set default language: *#0000# Send
set English language: *#0044# Send
software version: *#900# - On my phone this code power on the BT
*#901# - Power off BT
As you can see the code for firmware don't work so I can not povide you this information.

PLEASE HELP ME SOLVE THE ECHO PROBLEM.

If there is some one that can help me, I will cooperate.