ยง I recently bought on Ebay a ata 186 and to reset the previous configuration?
Here are the instructions
Step 1 
Mash the function button on the Cisco ATA.
Step 2 Enter the phone connected sullaporta then * then # 1 322873738
Step 3 Schicciate 3 as confirmed on the phone and hang up
Now you can access the ip address from DHCP on the ATA will acuisito WEB
