Loopback Operation

152-402-145-02, Issue 2

 

 

A3LB and A4LB Test Procedures

The H2TU-C can be looped back by sending the Addressable Office Repeater (AOR) LPBK activation code 1111-1111-0001-1110 (FF1E) for at least 5 seconds. This causes the H2TU-R-402 to enter the NLOC state. The H2TU-C Loopback Time-out (LBTO) setting determines the duration of this loopback unless it is overridden by the reception of a second identical 16-bit loopup command before the timer expires. When this time-out override state exists, the only way to loop the H2TU-R-402 down is to issue one of the three loopdown commands listed in Table 12. The automatic time-out mode is restored during subsequent loopback sessions.

Table 12 summarizes the codes required to execute Addressable 3 (A3LB) and Addressable 4 (A4LB) repeater loopback commands. All code sequences must be present for at least 5 seconds.

Table 12. Addressable Repeater Loopback Commands (A3LB and A4LB)

Name

Description

Binary Code (a) (Hexadecimal Equivalent)

NLOC

H2TU-R-402 loopup from NI

1111-1111-0001-1110 (FF1E)

 

 

 

CREM

H2TU-R-402 loopup from CI

0011-1111-0001-1110 (3F1E)

 

 

 

NREM

H2TU-R loopup from NI

1111-1111-0000-0010 (FF02)

 

 

 

CLOC

H2TU-R loopup from CI

0011-1111-0000-0010 (3F02)

 

 

 

SMJK

H2TU-R loopup from NI

11000-11000-11000 ...

 

 

 

SMJK

H2TU-R loopup from NI (b)

100000 100000 100000 ...

SMJK

H2TU-R loopup from NI (ESF-DL)

1111-1111-0100-1000 (FF48)

 

 

 

Loopdown

H2TU-C and H2TU-R loopdown from NI OR CI

11100-11100-11100 ...

 

 

 

Loopdown

H2TU-C and H2TU-R loopdown from NI OR CI

100-100-100 ...

 

 

 

Loopdown

H2TU-C and H2TU-R loopdown from NI OR CI (ESF-DL)

1111-1111-0010-0100 (FF24)

 

 

 

(a)The leftmost bit arrives first in all sequences. The detection algorithm functions reliably with a random 10-3Bit Error Ratio (BER) on the facility. The entire arming and loopback sequence can also be initiated at the remote H2TU-R location.

(b)Not supported by A4LB.

30

June 16, 2000

H2TU-R-402