Lantronix
ION x6010 User Guide
33493 Rev. F
Page 216 of 261
In-band Loopback Code Detect Procedure
This function enables detection and loopback of the fiber interface based on NIU Facility 2 (FAC2) loop-
back codes. Certain test devices (e.g., T-BERD 2310) can send in-band loopback codes to the local copper
(TP) interface, which are then transmitted to the remote device via the fiber. The remote device can de-
tect and react to this and activate and de-activate the loopback codes. For detection, these codes must
be sent for at least 5 seconds. Bit 5 loop codes are as follows:
•
Loop UP code: 5-bit ‘11000’
•
Loop DOWN code: 5-bit ‘11100’
The figure below shows data paths after the remote device receives the loop activate code (5-bit 11000)
for 5 seconds with SW 3 Switch 3-4 in the DOWN position.
Figure 22: Initiate a Loopback from a Test Set
The Inband Loopback Code Detector can track loopback activate/deactivate codes in a framed or un-
framed T1/J1 data stream. The received data stream is compared with the target activate/deactivate
code whose length and the content are pre-defined. When the received data stream matches the target
activate/deactivate code and repeats for 4 seconds, this register field indicates the detection of the in-
band loopback code.
Register fields IBLBA_S and IBLBD_S: In-band Loopback activate / deactivate code receive (from fiber)
status:
0
: No Inband Loopback deactivate signal is detected (default0
1
: The Inband Loopback deactivate signal is detected and then received over a period of more than
40 ms (T1) or 30ms (E1) with BER < 0.01.
The default setting is 0 (No Inband Loopback deactivate signal is detected).
1.
Set DIP Switch SW3 Switch 3-4 (Inband loopback selection) to the Down (L): Enabled position.
2.
See the specific test device (e.g., T-BERD 2310) documentation for the procedure to send in-band
loopback codes to the local copper (TP) interface.
