On ebay I found a very old Cisco ATA 186. Since the price was really cheap I thought to use it as ATA with Asterisk. Here are some notes on his configuration.
>> Reset Device
1) Take the phone off hook: the red button on the top of the ATA-186 will flashing.
2) Press the blinking red button on the ATA and dial 322873738#
3) Voice prompt will ask you to dial * to save changes you have just made: press * on your phone’s keypad.
4) Hang up the phone.
>> Flash firmware SIP version
1) Download the upgrade file (see linkografia) and unzip in your hard disk
2) Open a DOS prompt and switch to the directory where you have unzipped the downloaded zip file, then run the ata186us executable to get the PC ready for the request from the ATA
sata186us -any -d1 ATA030100SIP040211A.zup
Some instruction will appear in the dos terminal.
3) At this point, we need to turn to the Cisco ATA device, pickup the headset and press the ATA button on the top. Once the red ATA button is pressed, type the sequence as shown in DOS terminal.
>> Get Ip Address
1) Go off-hook on the phone attached to the ATA 186.
2) Click the red button on top of the ATA 186: you should hear interactive voice response (IVR) playing the configuration menu.
3) From the dialpad of the phone, press 80#
4) You should hear a voice playing the IP address of the ATA 186.
>> Access to web inteface
1) From browser connect to the web interface (default password: admin) using http://<asterisk ip address>/dev
2) In SIP Parameters set the parameters.
UID0/PWD0 = UserId/Password user for Phone1
DisplayName0 = Display Name for Phone1
UID1/PWD1 = UserId/Password user for Phone2
DisplayName2 = Display Name for Phone2
GkOrProxy = <asterisk ip address>
SIPRegOn = 1
Cisco Download Software
Asterisk phone cisco ATA18x on voip-info.org