For basic configuration of a SIP account on an Eltex VP-17P or Eltex VP-30P phone do the following:

1. Log in to the IP phone's web interface. The interface language can be changed in the upper right corner.
   Default:

   1. Login: admin

   2. Password: password
      

2. Go to the "IP Telephony" → "SIP Accounts" menu.
3. Check the "Account" checkbox. Additional settings will be displayed. 
4. Fill in:
   1. "Phone number"
   2. "Login"
   3. "Password"
5. In the "Proxy Addresses" section, enter the IP address of the PBX in the following fields:
   1. "Proxy Server"
   2. "Registration Server"
6. Click the "Apply" button at the bottom of the page.