Panasonic KX-TD500 System Reference Manual page 320

Table 2. shows how each combination of programming items works.
Account Code Entry
1
2
Always required
3
4
5
6
Not required
7
8
Validity Check
Not restricted, if a system
registered account code is
entered
Always checked
Restricted
Not restricted, if an
appropriate account code
is entered
Not checked
Restricted
Not restricted, if a system
registered account code is
Checked
entered
(if the account code
is entered)
Restricted
Not restricted, if an
appropriate account code
is entered
Not checked
Restricted
3-F-60
Restriction by Toll
Restriction Table
Table 2.