CANOGA PERKINS 2270 Fiber Optic Modem - Manual (Page 56)

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Canoga Perkins
5.2.2 Remote Loopback Test
To activate the Remote Loopback Test, set the Loop switch to REM and, after the Rx Data
Indicator begins to flash, set the switch back to OFF. For the "System Test Only" option, retain
the test switch in the REM position (refer to Section 5.2.3). The Local Loop On indicator will
remain on, indicating that the Remote Loopback has latched to the active state in the far-end
modem.
The Loop On Indicator at the far-end modem will flash to indicate that a remote loopback is active
at that end.
To release the Remote Loopback Test, set the Loop switch to REM and, after the Loop On
indicator begins to flash, set the switch back to OFF.
A Remote Loopback can also be activated through the electrical interface if it supports the Remote
Loopback control lead (refer to Section 3, "Data Interfaces," for pin numbers). This lead must be
driven to the ACTIVE (positive voltage) state and released after an appropriate delay period.
Table 5-A defines the types of Remote loopbacks that are possible with each configuration of the
ALT A and B jumpers. Figures 5-1, 5-4, 5-5 and 5-6 illustrate the "System Test Only," "Optical
Only," "Bi-Directional" and "Optical at Local End" forms of remote tests.
NOTE: If any modem locks up where the Loop On indicator stays ON, it will require
unplugging the modem and reinserting it, or recycling the power off and on to reset the
Figure 5-5. "Bi-
Directional"
Remote Loopback
Active
Figure 5-6. "Opti-
cal at Local End"
Loopback Active