Method for automatically adapting and configuring the speed of an ISDN terminal adapter to either 56 KBPS or 64 KBPS.

摘要

Method for automatically adapting and configuring the speed of a terminal adapter (30) to the rate 56Kbps or 64 Kbps which is used by a calling adapter (20). After the sending in the called terminal adapter (30) of the CONNECT message which is sent to the ISDN NETWORK in accordance with CCITT Q.931 Recommendations, the called TA (30) is initialized to a rate of 64 Kbps and then continuously transmits (204) an alignment pattern ALL_ONES while starting a first timing process (T1). This first timing process will cause the called TA to switch to a 56Kbps speed if the 64 Kbps validation process does not succeed. The method then involves the step of checking (206) the reception of a ALL_ZEROS pattern coming from said calling adapter (20) before the end of said first predetermined period (T1). If this case, a 64 Kbps validation process will be performed which comprises the checking whether a ALL_ONES pattern is received within a second period (T2), in which case the 64 Kbps rate configuration will be validated. On the contrary, if the ALL_ZEROS pattern is not received at the end of the first period (T1), a 56 Kbps rate validation process is initiated which is based on the detection of a so-called 56 Kbps pattern within the data flow. The 56 Kbps pattern is defined as being a number of n bytes with the first bit of every byte being set to a one. Additionally, the 64Kbps validation process involves the checking (210) of the continuous receiving of said ALL_ZEROS pattern during said first period (T1) as long as the ALL_ONES pattern is not yet received, and at the end of said first period (T1) validating (209, 213) the 64Kbps rate. <IMAGE>