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CHAPTER 4: Components
4.3 Front Cards

Table 4-2. Switch/Patch Front Cards

Model Interface Switch Patch Switched # of LEDs Alarms Mon. Bus Compatible
Cond. Slots Rear
Cards
SM705C RS-232/V.24 A/B 4-cavity 23 1 √√√SM720C
SM706C V.35 A/B 4-cavity 19 1 √√ SM721C
SM707C RS-530 A/B 4-cavity 23 1 √√√SM720C
SM708C DB15 SM722C
SM709C RJ-11 A/B — 4 1 SM723C
SM710C RJ-45 A/B — 8 1 SM724C
Front cards work with rear cards to manage lines. The front card contains the
switching and patching circuitry, while the rear card contains the cable interface
circuitry. The front card and the rear card mate when they are inserted into the
rack.
In a rack, there are 16 slots for front cards and 16 corresponding slots for rear
cards. The cards occupy one slot. The front cards are called Switch/Patch Cards.
S
WITCH
/P
ATCH
C
ARDS
Switch/patch cards provide A/B switching with optional patching capabilities.
Switch/patch cards are available for use with RS-232, V.35, RS-530, RJ-11, RJ-45,
and DB15 interfaces. Each switch/patch card occupies one slot.
Controls
A/B switch cards have a toggle switch with two settings: A and B. To change the
switch to the A position, move the toggle switch toward the A setting. To change
the switch to the B position, move the toggle switch toward the B setting.
LEDs
Switch/patch cards have some or all of the following LEDs:
• Switch position (green): Pro Switching System cards, where appropriate,
indicate switch position. For example, A/B switch cards indicate if the line is
currently switched to the A or B position.