ADC HiGain H2TU-C-202 User Manual page 30

Provisioning
SF Number
Fractional T1 (FT1) Option. Fractional T1 circuits can be used in feeder networks to provide frame relay
service. If such circuits are maintained by a DDS test group, then these circuits must respond to DDS/DS0 latching
loopback commands, the only tool test groups have at their disposal. A latching loopback, once it has been
initiated by the correct sequence, remains locked or "latched" until the correct loopdown sequence has been
detected.
The FT1 option, when enabled, allows the H2TU-C to respond to DS0 latching loopback commands and thus
support fractional T1 frame-relay applications. This is in addition to the standard full bandwidth T1 2-in-5 loopup
and 3-in-5 loopdown SmartJack commands. FT1 supports both the full T1 commands of ENA and the new DDS
latching loopback commands, which must also be enabled. (For more information about latching loopback
commands, refer to BellCore TA-TSY-000077, Issue 3, April 1986.)
The FT1 option supports both the DDS NI and DDS DS0 Data Port (DP) latching loopback sequences listed in
Table 11.
Enable Sequence
1
2A
2B
3
4
5
6
Disable/Loopdown
22
Table 10. SuperFrame Format
Terminal Framing Bit
1
2
3
4
5
6
7
8
9
10
11
12
Table 11. DDS NI and DS0 DP Latching Loopback Sequence
Minimum
Number of Byte Name
Bytes
35 Transition in Progress (TIP)
35 NI Loop Select Code (LSC)
35 DS0 DP Loop Select Code (LSC)
100 Loopback Enable Code (LBE)
35 All Ones
100 LBE
32 Far End Voice (FEV)
35 TIP
April 21, 2000
Frame Bits
SuperFrame Signaling Bit
1
0
1
0
1
0
152-202-115-04, Revision 04
0
0
1
1
1
0
Network Code
S 0 1 1 1 0 1 0
S 1 0 0 0 0 0 1
S 0 0 0 0 1 0 1
S 1 0 1 0 1 1 0
S 1 1 1 1 1 1 1
S 1 0 1 0 1 1 0
S 0 1 1 1 0 1 0
S 0 1 1 1 0 1 0
H2TU-C-202 List 1E