9. connection between two devices or a point-to-multipoint connection between one sender and
several receivers.
ە EĞƚǁŽƌŬ ůĂLJĞƌ: This third layer is responsible for routing packets through a network or
establishing a connection between two entities over many other intermediate systems.
Important functions are addressing, routing, device location, and handover between different
networks.
ە dƌĂŶƐƉŽƌƚůĂLJĞƌ: This layer is used in the reference model to establish an end-to-end
connection
ە ƉƉůŝĐĂƚŝŽŶůĂLJĞƌ͗ŝŶĂůůLJ͕ƚŚĞĂƉƉůŝĐĂƚŝŽŶƐ;ĐŽŵƉůĞŵĞŶƚĞĚďLJĂĚĚŝƚŝŽŶĂůůĂLJĞƌƐ ƚŚĂƚĐĂŶ
ƐƵƉƉŽƌƚĂƉƉůŝĐĂƚŝŽŶƐͿĂƌĞƐŝƚƵĂƚĞĚŽŶƚŽƉŽĨĂůůƚƌĂŶƐŵŝƐƐŝŽŶŽƌŝĞŶƚĞĚůĂLJĞƌƐ͘ƵŶĐƚŝŽŶƐĂƌĞ
ƐĞƌǀŝĐĞůŽĐĂƚŝŽŶ͕ƐƵƉƉŽƌƚĨŽƌŵƵůƚŝŵĞĚŝĂĂƉƉůŝĐĂƚŝŽŶƐ͕ĂĚĂƉƚŝǀĞĂƉƉůŝĐĂƚŝŽŶƐƚŚĂƚĐĂŶŚĂŶĚůĞ
ƚŚĞůĂƌŐĞǀĂƌŝĂƚŝŽŶƐŝŶƚƌĂŶƐŵŝƐƐŝŽŶĐŚĂƌĂĐƚĞƌŝƐƚŝĐƐ͕ĂŶĚǁŝƌĞůĞƐƐĂĐĐĞƐƐƚŽƚŚĞǁŽƌůĚͲǁŝĚĞ
ǁĞďƵƐŝŶŐĂƉŽƌƚĂďůĞĚĞǀŝĐĞ͘
'^D ͗ DŽďŝůĞ ƐĞƌǀŝĐĞƐ͕ ^LJƐƚĞŵ ĂƌĐŚŝƚĞĐƚƵƌĞ͕ ZĂĚŝŽ ŝŶƚĞƌĨĂĐĞ͕ WƌŽƚŽĐŽůƐ͕
ŽĐĂůŝnjĂƚŝŽŶĂŶĚĐĂůůŝŶŐ͕,ĂŶĚŽǀĞƌ͕^ĞĐƵƌŝƚLJ͕ĂŶĚEĞǁĚĂƚĂƐĞƌǀŝĐĞƐ
GSM Services
'^DŝƐƚŚĞŵŽƐƚƐƵĐĐĞƐƐĨƵůĚŝŐŝƚĂůŵŽďŝůĞƚĞůĞĐŽŵŵƵŶŝĐĂƚŝŽŶƐLJƐƚĞŵŝŶƚŚĞǁŽƌůĚƚŽĚĂLJ͘/ƚŝƐ
ƵƐĞĚďLJŽǀĞƌϴϬϬŵŝůůŝŽŶƉĞŽƉůĞŝŶŵŽƌĞƚŚĂŶϭϵϬĐŽƵŶƚƌŝĞƐ͘'^DƉĞƌŵŝƚƐƚŚĞŝŶƚĞŐƌĂƚŝŽŶŽĨ
ĚŝĨĨĞƌĞŶƚǀŽŝĐĞĂŶĚĚĂƚĂƐĞƌǀŝĐĞƐĂŶĚƚŚĞŝŶƚĞƌǁŽƌŬŝŶŐǁŝƚŚĞdžŝƐƚŝŶŐŶĞƚǁŽƌŬƐ͘^ĞƌǀŝĐĞƐŵĂŬĞ
ĂŶĞƚǁŽƌŬŝŶƚĞƌĞƐƚŝŶŐĨŽƌĐƵƐƚŽŵĞƌƐ͘'^DŚĂƐĚĞĨŝŶĞĚƚŚƌĞĞĚŝĨĨĞƌĞŶƚĐĂƚĞŐŽƌŝĞƐŽĨƐĞƌǀŝĐĞƐ͗
ďĞĂƌĞƌ͕ƚĞůĞĂŶĚƐƵƉƉůĞŵĞŶƚĂƌLJƐĞƌǀŝĐĞƐ͘
ŽŠ›Ž›ȱ œŽ›Ÿ’ŒŽœ͗ '^D ƐƉĞĐŝĨŝĞƐ ĚŝĨĨĞƌĞŶƚ ŵĞĐŚĂŶŝƐŵƐ ĨŽƌ ĚĂƚĂ ƚƌĂŶƐŵŝƐƐŝŽŶ͕ ƚŚĞ ŽƌŝŐŝŶĂůȱ
'^D ĂůůŽǁŝŶŐ ĨŽƌ ĚĂƚĂ ƌĂƚĞƐ ŽĨ ƵƉ ƚŽ ϵϲϬϬ ďŝƚͬƐ ĨŽƌ ŶŽŶͲǀŽŝĐĞ ƐĞƌǀŝĐĞƐ͘ ĞĂƌĞƌ ƐĞƌǀŝĐĞƐ
ƉĞƌŵŝƚƚƌĂŶƐƉĂƌĞŶƚĂŶĚŶŽŶͲƚƌĂŶƐƉĂƌĞŶƚ͕ƐLJŶĐŚƌŽŶŽƵƐŽƌĂƐLJŶĐŚƌŽŶŽƵƐĚĂƚĂƚƌĂŶƐŵŝƐƐŝŽŶ͘
dƌĂŶƐƉĂƌĞŶƚďĞĂƌĞƌƐĞƌǀŝĐĞƐŽŶůLJƵƐĞƚŚĞĨƵŶĐƚŝŽŶƐŽĨƚŚĞƉŚLJƐŝĐĂůůĂLJĞƌ;ůĂLJĞƌϭͿƚŽƚƌĂŶƐŵŝƚ
ĚĂƚĂ͘ĂƚĂƚƌĂŶƐŵŝƐƐŝŽŶŚĂƐĂĐŽŶƐƚĂŶƚĚĞůĂLJĂŶĚƚŚƌŽƵŐŚƉƵƚŝĨŶŽƚƌĂŶƐŵŝƐƐŝŽŶĞƌƌŽƌƐŽĐĐƵƌ͘
dƌĂŶƐŵŝƐƐŝŽŶ ƋƵĂůŝƚLJ ĐĂŶ ďĞ ŝŵƉƌŽǀĞĚ ǁŝƚŚ ƚŚĞ ƵƐĞ ŽĨ forward error correction (FEC)͕
ǁŚŝĐŚĐŽĚĞƐƌĞĚƵŶĚĂŶĐLJŝŶƚŽƚŚĞĚĂƚĂƐƚƌĞĂŵĂŶĚŚĞůƉƐƚŽƌĞĐŽŶƐƚƌƵĐƚƚŚĞŽƌŝŐŝŶĂůĚĂƚĂŝŶ
ĐĂƐĞŽĨƚƌĂŶƐŵŝƐƐŝŽŶĞƌƌŽƌƐ͘dƌĂŶƐƉĂƌĞŶƚďĞĂƌĞƌƐĞƌǀŝĐĞƐĚŽŶŽƚƚƌLJƚŽƌĞĐŽǀĞƌůŽƐƚĚĂƚĂŝŶ
ĐĂƐĞŽĨ͕ĨŽƌĞdžĂŵƉůĞ͕ƐŚĂĚŽǁŝŶŐŽƌŝŶƚĞƌƌƵƉƚŝŽŶƐĚƵĞƚŽŚĂŶĚŽǀĞƌ͘Non-transparent bearer
services ƵƐĞ ƉƌŽƚŽĐŽůƐ ŽĨ ůĂLJĞƌƐ ƚǁŽ ĂŶĚ ƚŚƌĞĞ ƚŽ ŝŵƉůĞŵĞŶƚ ĞƌƌŽƌ ĐŽƌƌĞĐƚŝŽŶ ĂŶĚ ĨůŽǁ
ĐŽŶƚƌŽů͘dŚĞƐĞƐĞƌǀŝĐĞƐƵƐĞƚŚĞƚƌĂŶƐƉĂƌĞŶƚďĞĂƌĞƌƐĞƌǀŝĐĞƐ͕ĂĚĚŝŶŐĂ radio link protocol
(RLP)͘dŚŝƐƉƌŽƚŽĐŽůĐŽŵƉƌŝƐĞƐŵĞĐŚĂŶŝƐŵƐŽĨ high-level data link control (HDLC)͕ĂŶĚ
ƐƉĞĐŝĂůƐĞůĞĐƚŝǀĞͲƌĞũĞĐƚŵĞĐŚĂŶŝƐŵƐƚŽƚƌŝŐŐĞƌƌĞƚƌĂŶƐŵŝƐƐŝŽŶŽĨĞƌƌŽŶĞŽƵƐĚĂƚĂ͘
19. ĐŽŶŶĞĐƚŝŽŶďĞƚǁĞĞŶƚǁŽƚĞƌŵŝŶĂůƐĂŶĚŝƐƵƐĞĚďLJŚŝŐŚĞƌůĂLJĞƌƐĨŽƌĐĂůůĞƐƚĂďůŝƐŚŵĞŶƚ͕ĐĂůů
ĐůĞĂƌŝŶŐĂŶĚĐŚĂŶŐĞŽĨĐĂůůƉĂƌĂŵĞƚĞƌƐ͘dŚŝƐůĂLJĞƌĂůƐŽƉƌŽǀŝĚĞƐĨƵŶĐƚŝŽŶƐƚŽƐĞŶĚŝŶͲďĂŶĚ
ƚŽŶĞƐ͕ĐĂůůĞĚdual tone multiple frequency (DTMF)͕ŽǀĞƌƚŚĞ'^DŶĞƚǁŽƌŬ͘dŚĞƐĞƚŽŶĞƐĂƌĞ
ƵƐĞĚ͕Ğ͘Ő͕͘ĨŽƌƚŚĞƌĞŵŽƚĞĐŽŶƚƌŽůŽĨĂŶƐǁĞƌŝŶŐŵĂĐŚŝŶĞƐŽƌƚŚĞĞŶƚƌLJŽĨW/EƐŝŶĞůĞĐƚƌŽŶŝĐ
ďĂŶŬŝŶŐĂŶĚĂƌĞ͕ĂůƐŽƵƐĞĚĨŽƌĚŝĂůŝŶŐŝŶƚƌĂĚŝƚŝŽŶĂůĂŶĂůŽŐƚĞůĞƉŚŽŶĞƐLJƐƚĞŵƐ͘
ĚĚŝƚŝŽŶĂůƉƌŽƚŽĐŽůƐĂƌĞƵƐĞĚĂƚƚŚĞďŝƐĂŶĚŝŶƚĞƌĨĂĐĞƐ͘ĂƚĂƚƌĂŶƐŵŝƐƐŝŽŶĂƚƚŚĞ
ƉŚLJƐŝĐĂůůĂLJĞƌƚLJƉŝĐĂůůLJƵƐĞƐpulse code modulation (PCM)ƐLJƐƚĞŵƐ͘WŝƐƵƐĞĚĨŽƌůĂLJĞƌ
ƚǁŽĂƚďŝƐ͕d^DĨŽƌd^ŵĂŶĂŐĞŵĞŶƚ͘Signaling system No. 7 (SS7)ŝƐƵƐĞĚĨŽƌƐŝŐŶĂůŝŶŐ
ďĞƚǁĞĞŶ ĂŶ D^ ĂŶĚ Ă ^͘ dŚŝƐ ƉƌŽƚŽĐŽů ĂůƐŽ ƚƌĂŶƐĨĞƌƐ Ăůů ŵĂŶĂŐĞŵĞŶƚ ŝŶĨŽƌŵĂƚŝŽŶ
ďĞƚǁĞĞŶD^Ɛ͕,Z͕sZƐ͕Ƶ͕/Z͕ĂŶĚKD͘ŶD^ĐĂŶĂůƐŽĐŽŶƚƌŽůĂ^^ǀŝĂĂ BSS
application part (BSSAP)͘
Localization and Calling
dŚĞĨƵŶĚĂŵĞŶƚĂůĨĞĂƚƵƌĞŽĨƚŚĞ'^DƐLJƐƚĞŵŝƐƚŚĞĂƵƚŽŵĂƚŝĐ͕ǁŽƌůĚǁŝĚĞůŽĐĂůŝnjĂƚŝŽŶŽĨ
ƵƐĞƌƐĨŽƌǁŚŝĐŚ͕ƚŚĞƐLJƐƚĞŵƉĞƌĨŽƌŵƐƉĞƌŝŽĚŝĐůŽĐĂƚŝŽŶƵƉĚĂƚĞƐ͘dŚĞ,ZĂůǁĂLJƐĐŽŶƚĂŝŶƐ
ŝŶĨŽƌŵĂƚŝŽŶĂďŽƵƚƚŚĞĐƵƌƌĞŶƚůŽĐĂƚŝŽŶĂŶĚƚŚĞsZĐƵƌƌĞŶƚůLJƌĞƐƉŽŶƐŝďůĞĨŽƌƚŚĞD^ŝŶĨŽƌŵƐ
ƚŚĞ,ZĂďŽƵƚƚŚĞůŽĐĂƚŝŽŶĐŚĂŶŐĞƐ͘ŚĂŶŐŝŶŐsZƐǁŝƚŚƵŶŝŶƚĞƌƌƵƉƚĞĚĂǀĂŝůĂďŝůŝƚLJŝƐĐĂůůĞĚ
ƌŽĂŵŝŶŐ͘ZŽĂŵŝŶŐĐĂŶƚĂŬĞƉůĂĐĞǁŝƚŚŝŶĂŶĞƚǁŽƌŬŽĨŽŶĞƉƌŽǀŝĚĞƌ͕ďĞƚǁĞĞŶƚǁŽƉƌŽǀŝĚĞƌƐ
ŝŶĂĐŽƵŶƚƌLJĂŶĚĂůƐŽďĞƚǁĞĞŶĚŝĨĨĞƌĞŶƚƉƌŽǀŝĚĞƌƐŝŶĚŝĨĨĞƌĞŶƚĐŽƵŶƚƌŝĞƐ͘dŽůŽĐĂƚĞĂŶĚ
ĂĚĚƌĞƐƐĂŶD^͕ƐĞǀĞƌĂůŶƵŵďĞƌƐĂƌĞŶĞĞĚĞĚ͗
¾
DŽďŝůĞƐƚĂƚŝŽŶŝŶƚĞƌŶĂƚŝŽŶĂů/^EŶƵŵďĞƌ;D^/^EͿ͗-The only important number
for a user of GSM is the phone number. This number consists of the ĐŽƵŶƚƌLJĐŽĚĞ
;Ϳ, theŶĂƚŝŽŶĂůĚĞƐƚŝŶĂƚŝŽŶĐŽĚĞ;EͿand theƐƵďƐĐƌŝďĞƌŶƵŵďĞƌ;^EͿ.
¾
/ŶƚĞƌŶĂƚŝŽŶĂů ŵŽďŝůĞ ƐƵďƐĐƌŝďĞƌ ŝĚĞŶƚŝƚLJ ;/D^/Ϳ͗ GSM uses the IMSI for internal
unique identification of a subscriber. IMSI consists of a ŵŽďŝůĞĐŽƵŶƚƌLJĐŽĚĞ;DͿ,
the ŵŽďŝůĞ ŶĞƚǁŽƌŬ ĐŽĚĞ ;DEͿ, and finally the ŵŽďŝůĞ ƐƵďƐĐƌŝďĞƌ ŝĚĞŶƚŝĨŝĐĂƚŝŽŶ
ŶƵŵďĞƌ;D^/EͿ.
¾
dĞŵƉŽƌĂƌLJŵŽďŝůĞƐƵďƐĐƌŝďĞƌŝĚĞŶƚŝƚLJ;dD^/Ϳ͗To hide the IMSI, which would give
away the exact identity of the user signalling over the air interface, GSM uses the 4
byte TMSI for local subscriber identification.
¾
DŽďŝůĞƐƚĂƚŝŽŶƌŽĂŵŝŶŐŶƵŵďĞƌ;D^ZEͿ͗Another temporary address that hides the
identity and location of a subscriber is MSRN. The VLR generates this address on
request from the MSC, and the address is also stored in the HLR. MSRN contains the
current ǀŝƐŝƚŽƌĐŽƵŶƚƌLJĐŽĚĞ;sͿ, the ǀŝƐŝƚŽƌŶĂƚŝŽŶĂůĚĞƐƚŝŶĂƚŝŽŶĐŽĚĞ;sEͿ, the
identification of the current MSC together with the subscriber number. The MSRN
helps the HLR to find a subscriber for an incoming call.
29. Unit:2 ȋ‹”‡Ž‡••Ȍ‡†‹— ‡••‘–”‘Žǣ‘–‹˜ƒ–‹‘ˆ‘”ƒ•’‡ ‹ƒŽ‹œ‡† ȋ ‹††‡
ƒ†‡š’‘•‡†–‡”‹ƒŽ•ǡ‡ƒ”ƒ†ˆƒ”–‡”‹ƒŽ•Ȍǡǡ ǡǡ.
dŚĞDĞĚŝĂĐĐĞƐƐŽŶƚƌŽů;DͿĚĂƚĂĐŽŵŵƵŶŝĐĂƚŝŽŶƉƌŽƚŽĐŽůƐƵďͲůĂLJĞƌ͕ĂůƐŽŬŶŽǁŶĂƐƚŚĞ
DĞĚŝƵŵĐĐĞƐƐŽŶƚƌŽů͕ŝƐĂƐƵďůĂLJĞƌŽĨƚŚĞĂƚĂŝŶŬĂLJĞƌƐƉĞĐŝĨŝĞĚŝŶƚŚĞƐĞǀĞŶͲůĂLJĞƌK^/
ŵŽĚĞů;ůĂLJĞƌϮͿ͘dŚĞŚĂƌĚǁĂƌĞƚŚĂƚŝŵƉůĞŵĞŶƚƐƚŚĞDŝƐƌĞĨĞƌƌĞĚƚŽĂƐĂ DĞĚŝƵŵĐĐĞƐƐ
ŽŶƚƌŽůůĞƌ͘ dŚĞ D ƐƵďͲůĂLJĞƌ ĂĐƚƐ ĂƐ ĂŶ ŝŶƚĞƌĨĂĐĞ ďĞƚǁĞĞŶ ƚŚĞ ŽŐŝĐĂů ŝŶŬ ŽŶƚƌŽů ;Ϳ
ƐƵďůĂLJĞƌ ĂŶĚ ƚŚĞ ŶĞƚǁŽƌŬΖƐ ƉŚLJƐŝĐĂů ůĂLJĞƌ͘ dŚĞ D ůĂLJĞƌ ĞŵƵůĂƚĞƐ Ă ĨƵůůͲĚƵƉůĞdž ůŽŐŝĐĂů
ĐŽŵŵƵŶŝĐĂƚŝŽŶĐŚĂŶŶĞůŝŶĂŵƵůƚŝͲƉŽŝŶƚŶĞƚǁŽƌŬ͘dŚŝƐĐŚĂŶŶĞůŵĂLJƉƌŽǀŝĚĞƵŶŝĐĂƐƚ͕ŵƵůƚŝĐĂƐƚ
ŽƌďƌŽĂĚĐĂƐƚĐŽŵŵƵŶŝĐĂƚŝŽŶƐĞƌǀŝĐĞ͘
LLC and MAC sublayers
Motivation for a specialized MAC
KŶĞ ŽĨ ƚŚĞ ŵŽƐƚ ĐŽŵŵŽŶůLJ ƵƐĞĚ D ƐĐŚĞŵĞƐ ĨŽƌ ǁŝƌĞĚ ŶĞƚǁŽƌŬƐ ŝƐ ĐĂƌƌŝĞƌ ƐĞŶƐĞ
ŵƵůƚŝƉůĞĂĐĐĞƐƐǁŝƚŚĐŽůůŝƐŝŽŶĚĞƚĞĐƚŝŽŶ;^DͬͿ͘/ŶƚŚŝƐƐĐŚĞŵĞ͕ĂƐĞŶĚĞƌƐĞŶƐĞƐƚŚĞŵĞĚŝƵŵ
;ĂǁŝƌĞŽƌĐŽĂdžŝĂůĐĂďůĞͿƚŽƐĞĞŝĨŝƚŝƐĨƌĞĞ͘/ĨƚŚĞŵĞĚŝƵŵŝƐďƵƐLJ͕ƚŚĞƐĞŶĚĞƌǁĂŝƚƐƵŶƚŝůŝƚŝƐĨƌĞĞ͘
/Ĩ ƚŚĞ ŵĞĚŝƵŵ ŝƐ ĨƌĞĞ͕ ƚŚĞ ƐĞŶĚĞƌ ƐƚĂƌƚƐ ƚƌĂŶƐŵŝƚƚŝŶŐ ĚĂƚĂ ĂŶĚ ĐŽŶƚŝŶƵĞƐ ƚŽ ůŝƐƚĞŶ ŝŶƚŽ ƚŚĞ
ŵĞĚŝƵŵ͘/ĨƚŚĞƐĞŶĚĞƌĚĞƚĞĐƚƐĂĐŽůůŝƐŝŽŶǁŚŝůĞƐĞŶĚŝŶŐ͕ŝƚƐƚŽƉƐĂƚŽŶĐĞĂŶĚƐĞŶĚƐĂũĂŵŵŝŶŐ
ƐŝŐŶĂů͘ƵƚƚŚŝƐƐĐŚĞŵĞĚŽĞƐƚǁŽƌŬǁĞůůǁŝƚŚǁŝƌĞůĞƐƐŶĞƚǁŽƌŬƐ͘dŚĞƉƌŽďůĞŵƐĂƌĞ͗
x ^ŝŐŶĂůƐƚƌĞŶŐƚŚĚĞĐƌĞĂƐĞƐƉƌŽƉŽƌƚŝŽŶĂůƚŽƚŚĞƐƋƵĂƌĞŽĨƚŚĞĚŝƐƚĂŶĐĞ
x dŚĞƐĞŶĚĞƌǁŽƵůĚĂƉƉůLJ^ĂŶĚ͕ďƵƚƚŚĞĐŽůůŝƐŝŽŶƐŚĂƉƉĞŶĂƚƚŚĞƌĞĐĞŝǀĞƌ
x /ƚŵŝŐŚƚďĞĂĐĂƐĞƚŚĂƚĂƐĞŶĚĞƌĐĂŶŶŽƚ͞ŚĞĂƌ͟ƚŚĞĐŽůůŝƐŝŽŶ͕ŝ͘Ğ͕͘ĚŽĞƐŶŽƚǁŽƌŬ
x ƵƌƚŚĞƌŵŽƌĞ͕^ŵŝŐŚƚŶŽƚǁŽƌŬ͕ŝĨĨŽƌĞ͘Ő͕͘ĂƚĞƌŵŝŶĂůŝƐ͞ŚŝĚĚĞŶ͟
+LGGHQDQG([SRVHG7HUPLQDOV
30. ŽŶƐŝĚĞƌƚŚĞƐĐĞŶĂƌŝŽǁŝƚŚƚŚƌĞĞŵŽďŝůĞƉŚŽŶĞƐĂƐƐŚŽǁŶďĞůŽǁ͘dŚĞƚƌĂŶƐŵŝƐƐŝŽŶƌĂŶŐĞŽĨ
ƌĞĂĐŚĞƐ͕ďƵƚŶŽƚ;ƚŚĞĚĞƚĞĐƚŝŽŶƌĂŶŐĞĚŽĞƐŶŽƚƌĞĂĐŚĞŝƚŚĞƌͿ͘dŚĞƚƌĂŶƐŵŝƐƐŝŽŶƌĂŶŐĞŽĨ
ƌĞĂĐŚĞƐ͕ďƵƚŶŽƚ͘ŝŶĂůůLJ͕ƚŚĞƚƌĂŶƐŵŝƐƐŝŽŶƌĂŶŐĞŽĨƌĞĂĐŚĞƐĂŶĚ͕ŝ͘Ğ͕͘ĐĂŶŶŽƚĚĞƚĞĐƚ
ĂŶĚǀŝĐĞǀĞƌƐĂ͘
Hidden terminals
x ƐĞŶĚƐƚŽ͕ĐĂŶŶŽƚŚĞĂƌ
x ǁĂŶƚƐƚŽƐĞŶĚƚŽ͕ƐĞŶƐĞƐĂ͞ĨƌĞĞ͟ŵĞĚŝƵŵ;^ĨĂŝůƐͿĂŶĚƐƚĂƌƚƐƚƌĂŶƐŵŝƚƚŝŶŐ
x ŽůůŝƐŝŽŶĂƚŽĐĐƵƌƐ͕ĐĂŶŶŽƚĚĞƚĞĐƚƚŚŝƐĐŽůůŝƐŝŽŶ;ĨĂŝůƐͿĂŶĚĐŽŶƚŝŶƵĞƐǁŝƚŚŝƚƐ
ƚƌĂŶƐŵŝƐƐŝŽŶƚŽ
x ŝƐ͞ŚŝĚĚĞŶ͟ĨƌŽŵĂŶĚǀŝĐĞǀĞƌƐĂ
Exposed terminals
x ƐĞŶĚƐƚŽ͕ǁĂŶƚƐƚŽƐĞŶĚƚŽĂŶŽƚŚĞƌƚĞƌŵŝŶĂů;ŶŽƚŽƌͿŽƵƚƐŝĚĞƚŚĞƌĂŶŐĞ
x ƐĞŶƐĞƐƚŚĞĐĂƌƌŝĞƌĂŶĚĚĞƚĞĐƚƐƚŚĂƚƚŚĞĐĂƌƌŝĞƌŝƐďƵƐLJ͘
x ƉŽƐƚƉŽŶĞƐŝƚƐƚƌĂŶƐŵŝƐƐŝŽŶƵŶƚŝůŝƚĚĞƚĞĐƚƐƚŚĞŵĞĚŝƵŵĂƐďĞŝŶŐŝĚůĞĂŐĂŝŶ
x ďƵƚŝƐŽƵƚƐŝĚĞƌĂĚŝŽƌĂŶŐĞŽĨ͕ǁĂŝƚŝŶŐŝƐŶŽƚŶĞĐĞƐƐĂƌLJ
x ŝƐ͞ĞdžƉŽƐĞĚ͟ƚŽ
,ŝĚĚĞŶƚĞƌŵŝŶĂůƐĐĂƵƐĞĐŽůůŝƐŝŽŶƐ͕ǁŚĞƌĞĂƐdžƉŽƐĞĚƚĞƌŵŝŶĂůƐĐĂƵƐĞƐƵŶŶĞĐĞƐƐĂƌLJĚĞůĂLJ͘
1HDUDQGIDUWHUPLQDOV
ŽŶƐŝĚĞƌƚŚĞƐŝƚƵĂƚŝŽŶƐŚŽǁŶďĞůŽǁ͘ĂŶĚĂƌĞďŽƚŚƐĞŶĚŝŶŐǁŝƚŚƚŚĞƐĂŵĞƚƌĂŶƐŵŝƐƐŝŽŶƉŽǁĞƌ͘
x ^ŝŐŶĂůƐƚƌĞŶŐƚŚĚĞĐƌĞĂƐĞƐƉƌŽƉŽƌƚŝŽŶĂůƚŽƚŚĞƐƋƵĂƌĞŽĨƚŚĞĚŝƐƚĂŶĐĞ
x ^Ž͕͛ƐƐŝŐŶĂůĚƌŽǁŶƐŽƵƚ͛ƐƐŝŐŶĂůŵĂŬŝŶŐƵŶĂďůĞƚŽƌĞĐĞŝǀĞ͛ƐƚƌĂŶƐŵŝƐƐŝŽŶ
x /ĨŝƐĂŶĂƌďŝƚĞƌĨŽƌƐĞŶĚŝŶŐƌŝŐŚƚƐ͕ĚƌŽǁŶŽƵƚ͛ƐƐŝŐŶĂůŽŶƚŚĞƉŚLJƐŝĐĂůůĂLJĞƌŵĂŬŝŶŐ
ƵŶĂďůĞƚŽŚĞĂƌŽƵƚ͘