Abstract: A system and method for compensating for slight variances between a first rate at which a far end modem transmits a series of data frames to a near end modem and a second rate at which the near end modem requires reception of the series of data frames. The modems comprise a data pump which receives data frames from the other modem at the first rate on a telephone line. The data frames are received by a data pump which provides the frames a character at a time to a controller coupled to the data pump. The controller places the characters into a pair of frame buffers in a memory coupled to the controller. The controller receives data frames from a vocoder at the second rate to be transmitted to the other modem. The controller attempts to provide data frames to the vocoder at the second rate in order to avoid distortion in the data frame flow, in particular, distortion in the compressed speech.

Abstract: A system and method for performing far end echo suppression of compressed speech frames in a telecommunications system. The system comprises a client modem and a server modem coupled together via a communications path. A controller in the server modem receives a first series of compressed speech frames from the client modem and provides the frames to a vocoder. Each of the frames includes voice encoded speech parameters. The controller maintains a history of a volume parameter value of the most recently provided frames to the vocoder. The vocoder decompresses the first frames to produce a first speech signal for transmission onto a telephone line. An echo of the speech signal may occur due to impedance mismatches between a hybrid in the server modem and the telephone line. The echo is received by the vocoder along with a second subscriber's speech signal from the telephone line.