It is possible to customize the behavior and appearance of Vtech devices using device overrides to program the line keys and memory keys. Some of the more commonly used overrides are listed on this page.
This Article pertains to Vtech VSP7XX and VCS phones. The newer VSP8XX phones have a different code structure.
Override Formatting
Overrides require NO spacing before or after the equals (=) sign, and the value given must be in quotes. Example: web.server_enable="1" This differs from the Vtech Admin Guide.
For all below features to work properly, we recommend using firmware version 2.0.3.2 or Higher.

Vtech Guides

To learn more about Vtech overrides in detail, please consult with the "Deskset Administrator and Provisioning Manuals" at the following link. Simply select your phone model and go to the downloads section to fine the Manual.
https://businessphones.vtech.com/products/sip-phones

Enable the Web Server

The local web server is disabled by default from our configuration files. To enable the web interface use the following override.

web.server_enable="1"

Programmable Keys

There are two types of Programmable Keys available on most Vtech phones. Programmable Feature Keys are side keys or buttons that are typically used for things like Call Park or BLF. Programmable Hard Keys are buttons like the 'hold' button that can be reconfigured to serve a different purpose.

Programmable Feature Keys (PFK)

The programmable feature key settings follow the format: pfk.x.[element], where x is the programmable feature key ID, ranging from 1 to 32.

Setting: pfk.x.feature
Description: Assigns a feature to PFK x.
Values: unassigned, line, dir, call log, redial, messages, dnd, dnd all, cfwd all, cfwd busy, cfwd no answer, quick dial, busy lamp field, acd, page, multicast page, park call, retrieve parked call, in call dtmf, callback, group call pickup, direct call pickup, prefix_dial, chp, hg, sf, lock_key, flash, xml app

The default SIP Account for each feature will be line 1, unless specified otherwise.

Setting: pfk.x.account
Description: Sets the SIP account used for the assigned feature (if applicable).
Values: 1–5
Default: 1
Quick Dial (Speed Dial)
Setting: pfk.x.quick_dial
Description: Sets the quick dial string to use if quick dial is assigned to PFK x.
Values: Text string (SIP URI)
Default: Blank

Example: Setting the second Programmable Feature Key to speed dial 7477778100.

pfk.2.feature="quick dial"
pfk.2.quick_dial="7477778100"
BLF

Note: BLF buttons do not have an 'available' LED. Users will show Orange/Red while Busy.

Setting: pfk.x.blf
Description: Sets the BLF string to use if Busy Lamp Field is assigned to PFK x.
Values: Text string (SIP URI)
Default: Blank

Example: Setting the third Programmable Feature Key to a BLF for extension 1000.

pfk.3.feature="busy lamp field"
pfk.3.blf="1000"
DTMF

For sending DTMF while on an active call.

Setting: pfk.x.incall_dtmf
Description: Sets the DTMF string if In-call DTMF is assigned to PFK x.
Values: Text string (SIP URI)
Default: Blank

Example: Setting the fourth Programmable Key to dial *80.

pfk.4.feature="in call dtmf"
pfk.4.incall_dtmf="*80"
Prefix

Prefix will prepend digits to an outgoing dial string. The Prefix is not shown to the user. This is useful for Intercom (*50).

Setting: pfk.x.prefix
Description: Enter a prefix to be dialed (hidden from the user) when the key is pressed. The prefix is added to any user-entered digits. %N can be used for substitution of user-entered digits. For example, *71%N# uses [*71] + [user-entered digits] + [#] as the outgoing dialing string.
Values: text string
Default: blank

Example: Setting key 16 to an Intercom Prefix. The user would press key 16 and then dial the extension in which they wish to start the Intercom.

pfk.16.feature="prefix_dial"
pfk.16.prefix="*50%N#"

Single Button Call Parking

For single button Call Parking, simply use a BLF with the orbit number as the destination.

Note you MUST be using version 2.0.3.2 or higher for a BLF key to perform a blind transfer while on an active call.
pfk.3.feature="busy lamp field"
pfk.3.blf="700"

Two Button Call Parking

Park Destination
Setting: pfk.x.park_destination
Description: If required by your service provider and sip_account.x.park_variant setting, enter a value for the park “orbit” or extension.
Values: text string
Default: blank

Example: Setting the fifth key to park a call in orbit '703'

pfk.5.feature="park call"
pfk.5.park_destination="703"
Park Retrieval
Setting: pfk.x.park_retrieval_source
Description: If required by your service provider and sip_account.x.park_variant setting, enter a value for the park “orbit” or extension.
Values: text string
Default: blank

Example: Setting the sixth key to retrieve a parked call from orbit '703'

pfk.6.feature="retrieve parked call"
pfk.6.park_retrieval_source="703"

Multicast Paging

You must set up to 10 Multicast Page Zones. Here is a zone 1 example.

page_zone.1.name="Multicast"
page_zone.1.multicast_address="224.0.1.116"
page_zone.1.multicast_port="5001"
page_zone.1.accept_incoming_page="1"

Set Multicast Page Zone to a PFK. The following override would set the second PFK to use Multicast Zone '1'.

pfk.2.feature="multicast page"
pfk.2.multicast_zone="1"

Distinctive Ring

The Distinctive Ring feature works by adding a department name to the Alert-Info header of the SIP INVITE message of internal calls. An endpoint that receives an invite can be configured to play a special ringtone based on the content.

ringersetting.1.ringer_text="sales"
ringersetting.1.ringer_type="2"

This example will cause any Vtech phone to use Ringer 2 whenever a call is received from a member of the "sales" Department.