Thanks, Mike.
Now the control unit works again. Actually, I chose on command line s (system) and then c (setup default 1 (control)). After that I managed to make ethernet connection to the control unit, and now I can set settings by using my web browser.
Thanks very much for your advises, Mike. Now I can get my things work again. FB!
So, I installed Puttytel.exe on my WIN7 laptop and connected serial cable between the control unit (front side female 9-pin D-connector) and laptop COM1. By using Puttytel.exe and setting serial parameters as Mike told me, I got the connection to my unit. Below is the text output on my command window. One can see the commands told above. If this might interest someone.
=========================
a: audio
c: codec
d: debug
e: extio
f: flash
i: sip
l: led
q: audio quality
p: power
r: radio
s: sys
=========================
1: setup edit
2: setup view
3: setup clear
4: sntp
5: rtc
6: wdt reset
7: dns query
8: show network info
9: STUN test
0: memory
a: UDP send
b: UDP receive
c: Setup default 1(Control)
d: Setup default 2(Radio)
q: exit
73 Kari OH3BJL