A multiframe structure is adapted to transmit narrowband telephony signals over a broadband cable link (BCL) carrying also video or television signals. The telephony transmission occurs according to classical telephony protocols such as the channel associated signalling (CAS) or the common...http://www.google.de/patents/US5848070?utm_source=gb-gplus-sharePatent US5848070 - Multiframe structure and handling protocol for a telecommunication network 
