公开(公告)号：US20060095581A1

公开(公告)日：2006-05-04

申请号：US11220089

申请日：2005-09-06

Applicant: Murtaza Ali ,  Shahedolla Molla ,  Narasimhan Venkatraman ,  Channamallesh Hiremath ,  Umashankar Iyer ,  Udayan Dasgupta ,  Austin Hunt ,  Dennis Mannering

Inventor： Murtaza Ali ,  Shahedolla Molla ,  Narasimhan Venkatraman ,  Channamallesh Hiremath ,  Umashankar Iyer ,  Udayan Dasgupta ,  Austin Hunt ,  Dennis Mannering

IPC: G06F15/16

CPC classification number: H04M11/062

Abstract: A client premises digital subscriber line (DSL) modem having multi-mode capability is disclosed. In initialization, the modem estimates whether channel conditions are such that digital processing of the received data according to a lower data rate DSL standard, such as ADSL2, may result in a higher effective data rate than receipt and processing according to a higher data rate DSL standard, such as ADSL2+. If so, the DSL modem configures itself, such as by configuring its filter characteristics and sampling frequency, to receive and process data according to the lower data rate DSL standard; the transmitting modem, for example at a central office or service area interface, may continue to operate according to the higher data rate standard (with its bit loading corresponding to a subset of subchannels). The receiving DSL modem processes the payload data according to the lower standard, while processing control messages according to the higher standard.

公开(公告)号：US06707902B2

公开(公告)日：2004-03-16

申请号：US09819869

申请日：2001-03-28

Applicant: Thomas Leyrer ,  Umashankar Iyer ,  Sharmila Kannangara

Inventor： Thomas Leyrer ,  Umashankar Iyer ,  Sharmila Kannangara

IPC: H04M300

CPC classification number: H04L7/10 ,  H04L2007/047 ,  H04M11/066

Abstract: A method of resynchronizing data transfer between a first modem assigned to a central office and connected by a dedicated line a second modem assigned to a remote subscriber following a fault caused by a ringing signal. A ringing ID is set up in the central office modem as soon as a ringing signal is to be sent to the subscriber modem, and a ringing alert is transferred to the connected subscriber modem. Transmission of the pilot tone accompanying the data transfer set by the central office modem is interrupted as is the clock frequency synchronization implemented during data transfer in the subscriber modem with the pilot tone as reference. The two modems are put on hold to save the characteristic parameters for the momentary data transfer followed by transfer of the ringing signal via the dedicated line to the subscriber modem. The ringing ID is reset in the central office modem, the pilot tone is resent via the central office modem and reinstating synchronization of the clock frequency reinstated in making use of the pilot tone as reference. The prior data transfer mode of using the saved characteristic parameters and the subscriber modem is synchronized to the data stream coming from the central office modem by searching for and detecting specific code groups occurring regularly in the transferred data stream.

Abstract translation: 一种在分配给中心局的第一调制解调器和由专用线路连接的第一调制解调器之间的数据传输的方法，所述第二调制解调器在由振铃信号引起的故障之后分配给远程用户。 一旦振铃信号被发送到用户调制解调器，就会在中心局调制解调器中建立振铃ID，并且将振铃警报传送到所连接的用户调制解调器。 伴随着由中心局调制解调器设置的数据传输的导频音调的传输也与在以导频音作为参考的用户调制解调器中的数据传输期间实现的时钟频率同步被中断。 两个调制解调器被保留以保存用于瞬时数据传输的特征参数，随后通过专用线将振铃信号传送到用户调制解调器。 振铃ID在中心局调制解调器中复位，通过中心局调制解调器重新发送导频音，并恢复使用导频音恢复时钟频率的同步作为参考。 使用保存的特征参数和用户调制解调器的先前数据传输模式通过搜索和检测在传送的数据流中定期出现的特定代码组，与来自中心局调制解调器的数据流同步。