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CHAPTER 3: Configuration
SGND and FRGND (JB4)
In the connected position, this strap links signal ground and frame ground. In the
open position, signal ground is disconnected from frame ground.
JB4
Position 1 & 2 = SGND and FRGND Connected*
Position 2 & 3 = SGND and FRGND Not Connected
*Default setting
3.3.3 DB15 R
EAR
C
ARD
(X.21) S
TRAP
S
ETTINGS
Figure 3-23 shows strap locations for the DB15 (X.21) rear cards. These straps
determine various grounding characteristics for the terminal interface and
twisted-pair lines. JB3 and JB4 are user configurable.
Figure 3-23. Strap locations.
Table 3-11 provides an overview of interface strap functions for the rear interface
cards. Following the table overview are detailed descriptions of each strap’s
function.
JB3
JB4
