Abstract: A modified version of the operating communication program of a stored program controlled apparatus is installed with the aid of a downloadable start address specification means, optionally realized with an EEPROM memory. The start address specification means stores information that is downloaded through a communication port in the apparatus, and that information is used in defining the address from where the communication programs are initiated. In accordance with the method of this invention, downloading of the entire new set of programs is effected by first downloading a segment of the essential portion of the new package of programs. Control is then transferred to the new segment by downloading appropriate information into the start address specification means. Thereafter, utilizing the downloaded essential portion of the new package of programs, the remainder of the new package is downloaded.

Abstract: A transmitting Mu-law modem creates a probe signal by modifying the 7th bit of each of a number of PCM samples during the "hand-shaking" phase of a data connection. Furthermore, the transmitting Mu-law modem only makes this modification on those PCM samples that fall into the range of segment 1 as defined in CCITT Recommendation G.711. Similarly, a receiving Mu-law modem searches for this known pattern. Upon detection of this pattern, the receiving Mu-law modem provides an acknowledgment signal and both modems subsequently switch to a digital-mode of operation. On the other hand, if, in fact, there is a least one analog link in the data connection, the probe signal becomes distorted and, since the receiving Mu-law modem does not detect the probe signal, handshaking is completed in the standard fashion.

Abstract: The present invention enables a dial modem capable of simultaneous voice and data (SVD) operation and connected to a conventional telephone set to automatically select between SVD operation, analog voice operation and digital data operation when transmitting or receiving communication signals based on the position of the telephone set's hookswitch. The invention includes a hookswitch position detector, connected to the telephone set, for sensing the current position of the hookswitch, and a signal controller, connected to the hookswitch position detector. The signal controller may be configured to enable either of two hookswitch control option settings. The hookswitch control option settings determine the manner in which the controller responds to the current hookswitch position ("on-hook" or "off-hook") detected by the hookswitch position detector.

Abstract: A transmitting Mu-law modem creates a probe signal by modifying the 7th bit of each of a number of PCM samples during the "hand-shaking" phase of a data connection. Furthermore, the transmitting Mu-law modem only makes this modification on those PCM samples that fall into the range of segment 1 as defined in CCITT Recommendation G.711. Similarly, a receiving Mu-law modem searches for this known pattern. Upon detection of this pattern, the receiving Mu-law modem provides an acknowledgment signal and both modems subsequently switch to a digital-mode of operation. On the other hand, if, in fact, there is a least one analog link in the data connection, the probe signal becomes distorted and, since the receiving Mu-law modem does not detect the probe signal, handshaking is completed in the standard fashion.

Abstract: A modified version of the operating communication program of a stored program controlled apparatus is downloaded by first downloading a segment of the new package of programs which contains the essential portion of the new programs. Control of the apparatus is then transferred to the new program segment. Thereafter, utilizing the downloaded essential portion of the new package of programs, the remainder of the new package of programs is downloaded.