Hardware Straps; Tip And Ring Polarity; Ground Option Strap - Black Box 325 User Manual

4.3 Hardware Straps

4.3.1 T R P
IP AND ING
Some telephones are sensitive to tip and ring polarity. If a dial tone is detected after dialing, reverse
these two straps.
4.3.2 G O
ROUND PTION
Signal ground is normally connected to chassis ground. If interference exists, isolate signal ground from
chassis ground.
OLARITY
NORM
Normal tip and
ring connection
Figure 4-4. Tip and Ring Polarity Jumper.
S
TRAP
SIG GND
Figure 4-5. Ground Option Strap.
NORM
REV REV
Reverse tip
and ring
connection
CH GND
Signal ground connected to
chassis ground selected
CHAPTER 4: Option Selection
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