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Provisioning LTPH-UM-1049-02, Issue 2
24 January 9, 2002 H2TU-C-319 List 4E
used to embed SPRM or NPRM into the datalink toward the network. During conversion, frame bit errors are
regenerated to ensure transparency.
The HDSL2 system attempts to find ESF or SF framing or determines that no framing exists. The DS1 framing is
then synchronized with the HDSL2 frame. If the framing is lost, the system generates an Out-of-Frame (OOF)
defect which results in UAS-P. As a result, the system reverts to frame search mode.
This option has the following settings:
• OFF: No frame conversion takes place. All framing issues are determined by the FRMG option settings of
AUTO and UNFR.
• ACON: This is the automatic conversion setting. If the system detects ESF from the network and SF from the
CPE, it automatically converts the CPE SF to ESF toward the network as well as the network ESF to SF
toward the CPE.
Upon power-on-reset, after loopdown, or after changing the frame conversion option, the framing needs to
be re-established before a complete conversion takes place. If there is a failure condition (LOS, AIS, or LOF)
during steady state, the previous conversion state is maintained to ensure continuity when the system returns
from the failure condition.
If SF is received from the network, the H2TU-R forces an ESF toward the network for about 1.5 seconds.
This signals to the far-end PM-NIU at the network boundary that frame conversion is requested. If the far-end
PM-NIU is capable of conversion, it changes the framing to ESF. If not, then the H2TU-R reverts to SF and
does not apply any conversion.
If an ESF is received from the CPE, it is passed on to the network, and the network’s inbound framing is
passed on to the CPE.
• FCON: This is the forced conversion setting. Table 8 below lists the HiGain HDSL2 responses to both the
ACON and FCON settings for the CONV option. The responses are identical, except in cases 3 and 4. In these
cases, the FCON reply is attempting to force the network (or the far-end PM-NIU) to send ESF. It also alerts
the CPE with an AIS alarm pattern while forcing the ESF to the network. Continuity is maintained as for
ACON. Table 9 on page 25 and Table 10 on page 25 list the ESF and SF frame formats, respectively.
Table 8. Response to H2TU-R DS1 Frame Conversion Options
Case Number NET Transmit CPE Transmit
ACON Option FCON Option
NET > CPE
NET < CPE
NET > CPE
NET < CPE
1 ESF SF ESF → SF
ESF ← SF
ESF → SF
ESF ← SF
2 ESF ESF ESF → ESF
ESF ← ESF
ESF → ESF
ESF ← ESF
3 SF ESF SF → SF
ESF ← ESF
SF → AIS
ESF ← ESF
4 SF SF SF → SF
SF ← SF
SF → AIS
ESF ← SF