Calling Line Identifier with VMWI
CMX612
Figure 9b : Bellcore On-hook System Signals
Other On-hook Systems
ETS 300 659-1 and ETS 300 778-1 also allow for systems where the FSK transmission is preceded by a
Dual Tone Alerting signal similar to that used by BT but without a line reversal (Section 6.1.2a) or by a
Ringing Pulse Alerting Signal (Section 6.1.2b).
The U.K. CCA (Cable Communications Association) specification TW/P&E/312 precedes the FSK signals
by a 200 to 450ms ring burst. The use of ac and dc line terminations during FSK reception is optional.
Mercury Communications Ltd. specification MNR 19 allows for either the BT system or that specified by
CCA.
As these are all slight variants on the BT and Bellcore systems, they can also be handled by the
CMX612.
ã 2002 Consumer Microcircuits Limited
15
D/612/3
CMLMICRO [ CML MICROCIRCUITS ]
