Specification Sheet

7
In addition to reducing the security of the cylinder, cross keying
usually imposes limits on the exibility and expansion of the
overall keying system. This is especially true of uncontrolled
cross keying. For these reasons, it is strongly recommended to
allow personnel to carry more than one key. Cross keying should
be discouraged whenever possible. However. when cross keying
is required, it is specied as follows, and should be summarized
at the beginning of each order.
Cross Keying
Convenience May Reduce Cylinder Security and Hinder System Expansion
Whenever two or more different keys such as AA1 and AA2
are both required to operate the same cylinder, the cylinder’s
security is reduced. This is called cross keying. When the cross
keying occurs under all the same higher level keys, such as
AAI and AA2, it is known as controlled cross keying. When it
combines keys under different higher level keys, such as AAI
and AB1, it is known as uncontrolled cross keying.
Case #1
Cylinder requires its own change key. The illustration depicts part
of a small medical building where two doctors share a common
reception area. The receptionist gets the AA3 key. Each doctor
carries a key which operates only one ofce, but is also cross
keyed into the entrance from the corridor.
Determine the symbol of the change key (example: AA3). Then
prex the letter X (example: XAA3). Then list all keys which are to
operate in an “operated by...” phrase. Example. “XAA3 operated
by AA1, AA2, AA and A”. Note that X is a cylinder specication
only. The keys for cylinder XAA3 are designated AA3.
Case #2
A cylinder does NOT require its own change key. This illustration
depicts a section of a oor in a dormitory. Each student’s
bedroom key operates the hall door lock. There is no need to
construct a key which operates only the hall door.
In this case, place an X at both the beginning and end of the
symbol and a number between them. Example: X1X, X2X,
etc. Again, always include the “operated by . . . phrase with a
complete listing of key symbols to operate.
XAA3
AA1
AA2
XAA3 Operated by AA1, AA2, AA and A
AA1 AA2
X1X Operated by AA1 through AA6, AA and A
AA3
AA4 AA5 AA6
X1X
K E Y I N G S Y S T E M S
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