Loopback Operation
150-388-125-01, Revision 01
38
September 15, 1998
HLU-388 List 2E
I
NITIATING
M
ANUAL
L
OOPBACK
S
ESSIONS
A manual loopback session allows you to select one of four HiGain system loopbacks.
To initiate a manual loopback session:
1
Press both the MODE and SEL buttons on the front panel for at least 3 seconds. The following message
appears on the front panel display:
MAN LPBK
followed by the message:
NLO?
2
Do one of the following:
•
To execute an NLOC loopback, press the SEL button. The message changes from
NLO
? to
NLOC
.
•
To execute an NREM loopback:
a
Press the MODE button. The message changes from
NLO?
to
NRE
? in a non-doubler system (or
ND1 in a doubler system).
b
Press the SEL button to execute the NREM loopback in a non-doubler system (or NDU1 in a doubler
system).
In this manner all eight loopbacks can be initiated, in the following order: NLOC, NDU1, NDU2, NREM,
CLOC, CDU2, CDU1, CREM.
3
To execute a CRE loopback, press the MODE button again.
4
To execute a CLO loopback, press the MODE button a third time.
These same loopbacks can be initiated from the RS-232 Craft port by choosing the Loopback Mode, option D,
from the Main Menu. This displays the Loopback Menu (
) from which any of the loopbacks
can be initiated or terminated.
Any of the HiGain loopbacks can be executed using the MODE and SEL buttons.
In general, to execute a manual loopback session using the MODE and SEL buttons:
•
The next loopback option can be presented by pressing the MODE button, however, the
previously executed loopback remains active until the SEL button is pressed and a different
loopback is activated.
•
If neither button is pressed for a period of 30 seconds and no loopback is in effect, the
manual loopback session terminates and the normal margin displays reappear.
•
If any loopback is in effect, the 30-second timeout is inhibited. The active loopback and the
manual loopback session continue until the loopback times out in accordance with the
LBTO setting.
•
Only the SMJK loopback can exist with other networks at any given time.
•
Pressing both buttons, again for three seconds, terminates any active loopback, ends the
Manual loopback session and returns the display to normal mode.
