5.1
Configuring The Services and Interface Boards
The DXP Plus extracts clocking information from the central office (CO) that supplies the T1 lines, and routes
this information to the DXOPT–SYN sync card. The sync card uses this clocking information to derive the
synchronizing signal for the DXPT1 board’s transmit clock signal. Therefore, the DXPT1 board’s transmit clock
is slaved to the CO supplying the T1 lines. If there is only one CO supplier, that source is the primary clock
source; however, if there are two different suppliers of T1 lines, use the more reliable T1 supplier as the primary
source and the other T1 supplier as the secondary source.
You must designate one DXPT1 board as the primary board. Choose this board from among those boards that
interface the T1 lines supplied by the primary CO supplier. Designate the primary board by placing straps on the
DXSRV–PLS services board and by setting DIP switches on the expansion cabinet interface boards.
If you system has only one CO supplier, you do not need to designate a secondary board; however, if the system
has a second CO supplier of T1 lines, you must designate one DXPT1 board as the secondary board. Choose this
board from among those boards that interface the T1 lines supplied by the second CO supplier. Designate the
secondary board by placing straps on the services board or by setting DIP switches on the expansion cabinet
interface boards.
If you designate primary and secondary boards to the system even though there is only one CO clock source, the
DXOPT–SYN card functions as though it is receiving two clock signals and lights both PRI and SEC LEDs on
the front edge of the card.
IMI89–193
Installing The DXPT1 Line Board
18 – Installing The DXPT1 Line Board
