of bittings, and we’ll keep it simple: theoreticals - Total possible number of different combinations available from a KBA — just the numbers, all the numbers! practicals (Useables) - You can cut them. undesirables - You’d rather not use them forbiddens - Violates MACS; cannot be used. What’s a Key Symbol? It’s not a bunch of stuff just stamped on a key. To the contrary, it’s one part of a high- ly organized way of identifying exactly where a key fits into a master key system. key symbol - n. a designation used for a key combination in the standard key cod- ing system, e.g., A, AA, AA1, etc. standard key coding system (SKCS) - n. an industry standard and uniform method of designating all keys and/or cylinders in a master key system. The designation automatically indicates the exact function and keying level of each key and/or cylinder in the system, usually without further explanation. The symbols within a SKCS will not be stamped on the key itself. Rather, the direct or indirect key code will be. But, the SKCS designation will be used to identify that key in the system. It will tell us what locks that key will operate and can be used to order additional cut keys from a manufacturer without any confusion. Levels of Keying The levels of keying are not quite like high, medium or low, but sort of. levels of keying - n. pl. the divisions of a master key system into hierarchies of 46 KEYNOTES JULY/AUGUST 2017 “Remember, you may never have the need to set up your own master key system, but it’s still vital that you have a basic understanding of the elements involved.” access, as shown in the following tables. Note: the standard key coding system has been expanded to include key symbols for systems of more than four levels of keying. Figure 6 shows this concept. It simply breaks down the TMK into masters below it and what they will be called. The more masters below it, the less change keys to be had under each. Key Specs Before one can master key, one must de- termine his or her key (system) specifica- tions. These items include: Number of depths Depth increment Progression type Number of spaces MACS specification Most of these items can be found on a key bitting specifications page. Figure 7 is where a picture can save us a 1,000 words. Cross Keying!? Basically, it’s a bad idea. What is it? cross keying - n. the deliberate process of combinating a cylinder (usually in a master key system) to two or more dif- ferent keys that would not normally be expected to operate it together. There exists intentional and uninten- tional cross keying. Maison keying is an example of intentional cross keying. Here you will add master pins allowing many more keys to operate that cylinder than just one change key. The more chambers with more master pins, the more keys that will operate that lock. Also, these cylinders are much easier to pick open. maison key system - [from the French, meaning “house” key system] a keying system in which one or more cylinders are operated by every key (or relatively large numbers of different keys) in the system; e.g., main entrances of apartment buildings operated by all individual suite keys of the building. Finding out your “alleged change key” not only opens the janitorial closet, but it also opens the door to the president’s office is unintentional cross keying and is also known as key interchange (and, by the way, how did you know that it opened that door?). Cross keying is not only less secure be- cause it usually relies on additional mas- ter pins in a cylinder, but it will also cause a number of potentially useable bittings to be crossed off the bitting list — thus, lost combinations. So, when would cross keying be used? Be- low are three easy-to-understand examples. Maybe OK: “All teachers’ keys in the el- ementary school shall operate the chil- dren’s restrooms.” Not So OK: “All tenant keys shall operate the common entry doors.” Really, Really Bad: “Many keys will operate a variety of different cylinders in the dormitory.” WWW.ALOA.ORG
