22
SYNC/ASYNC FIBER OPTIC MODEM
Table 3-1. Fiber Optic Modem Strap Selection
Strap Identity Function
Possible Settings
Factory Setting
J1
Enables or disables
EN
EN
V54 DIS
DIG.LOOP from
DIS
remote pattern.
J2
Selects the transmit
ON
ON
CARRIER
carrier mode. When
CNTRL
“ON,” transmit carrier
is constantly “ON.”
When “CNTRL,” transmit
carrier is “ON” only
when RTS is high.
J3
Selects the transmit
EXT
XMT CLK
timing signal from either:
INT
INT
internal clock, external
RCV
clock, or receive clock.*
ASY
J4
Selects the delay time
0
RTS-CTS
(in ms) between RTS
9
9 ms
DLY (ms)
and CTS.
70
J6
Enables activation of
ON
ON
SW EN
PATT, REM, ANA, DIG
OFF
pushbuttons on the
front panel.
J7
Enables RLB test from
EN
RLB DTE
the DTE interface pins.
DIS
DIS
J8
Enables LLB test from
EN
ALB DTE
the DTE interface pins.
DIS
DIS
* When two Fiber Optic Modems are used, one modem should be configured as
RCV clock and the other as INT or EXT clock.
