Seems to me that Toll restriction is (and should be) a standard feature of any PBX phone system. I am not sure why this is an unsupported / undocumented feature of this D-Link system.
Anyway, just in case anyone else is needing to implement a Toll Restriction feature (on PSTN lines)...
It can be done. The following is applicable in the US. Here is the step by step. (Though I take no responsibility for the consequence of anyone using these instructions.)
First, determine the IP address of the phone on which to enable toll restriction.
One way to do this - in Microsoft Response Point Adminstrator - point your cursor at the phone in question. Record the IP Address in the tool tip popup that appears.
For this example, lets say the IP is 192.168.0.121
Open your browser and type the following IP address: http://192.168.0.121:9999
This will open the web configuration page of the phone.
(You may want to change the username and pw to this config page to protect your setting changes. However be forewarned, I do not know if there is a way to reset the phone back to the default - (blank) username / password if that password is forgotten. I do not see a Reset button on the phone anywhere. So if you forget the un/pw, I do not know what you could do... Mlachake??)
Click on the "Phone" tab at the top, then on "Dial Plan" on the left pane.
A short explanation of the default setting you see here:
Prefix 1-7
All with the following settings: Min digit: 3, Max digit: 3, Del Digits: 0, Add: (blank)
All dialing starting with digits 1 - 7 are assumed to be 3 digt internal extension numbers. After you dial a 3 digit # starting with 1 - 7, the phone will immediately dial that #.
8 is the digit reserved for VOIP calls, and 9 is the standard prefix to grab an outside PSTN line.
If you want to limit dialing long distance numbers but want to allow the phone to dial toll free numbers, add the following four Dial Plans entries:
Prefix: 91800, 91866, 91877, 91888
Set each with the following settings:
Min digit: 12, Max digit: 12, Del Digits: 0, Add: (blank)
You may exclude adding the above 4 entries, if you do not want the phone to even be able to dial these toll free prefixes.
Then add the following Dial Plan to disallow the phone from dialing any long distance numbers - i.e. numbers starting with 1 then the area code...:
Prefix: 91
Min digit: 12, Max digit: 12, Del Digits: 12, Add: 799
If the phone is allowed to dial long distance numbers but you want to limit it from just dialing 900 numbers, add the following dial plan entry instead of the one above:
Prefix: 91900
Min digit: 12, Max digit: 12, Del Digits: 12, Add: 799
Save and apply the changes.
Now when someone tries to dial an unauthorized long distance / toll #, the phone will dial extension 799 instead. In the Administrator, you could add a user named "Unauthorized Dialing" at extension # 799, and thereafter be able to review the history of who and when people are trying to dial out to these numbers.
You could of course modify what you put in the Add field or otherwise modify the dialing plan to suit your needs, but something like this addresses my needs.
Another useful (and possibly life-saving) entry to add to (ALL) phones:
Prefix: 911
Min digit: 3, Max digit: 3, Del Digits: 3, Add: 9911
This dial plan will dial 9911 when a user picks up the phone and dials just 911. In order to dial the emergency-911 phone number, you actually need to dial 9911 on this phone system. Someone in an emergency situation (or someone unfamiliar with the phone system) may just pick up the phone and dial 911 - AND NOT GET THE CALL THROUGH!. Adding this dial plan entry will accept 911 (in addtion to 9911) to dial out to the emergency-911 phone number.