The PIN is a 4 byte (32bit) integer. Leading zeros are stripped away, so 0100 = 100. The maximum size is 2,147,483,647.
So any number greater than this, will not be accepted. This is both a hardware (MSTC & BasicX) as well as Axcys Integrated Security Software. Global recommends a maximum PIN Size of 9 digits in these cases.
Axcys Facility Security Management System:
64 Bit PINs available beginning with certain versions of Axcys Facility Security Management System that use ExclypX Keypad models purchased after December 2014, PIN lengths of 18 digits and/or up to 20 Alpha Numeric codes may be used.
If you are unsure which product you have, please consult with Global.
** Maximum length of PIN is dependant on which OS version you have. To use the extended PIN length, you must be using a 64bit Operating System.
NRC Codes Vs. Tenant Codes:
It is a good idea to use different length codes for NRC and Tenants. This will help prevent unintended duplication. If all Tenants have 8 digit code, then make the NRC's have 6 digit. If all Tenants have 6 digits, make NRC's have 8.
Length of Code:
The longer the code, the harder to randomly guess the code. However, too long of a code can be difficult for some people. Please judge the code length by your local demographics, and individual preferences.