| 摘要 |
<p>PURPOSE:To monitor a D-channel data of a user network interface and to attain diagnosis of layer circuits 1, 2 of an ISDN terminal equipment by providing a switching circuit so as to select the reception of a D echo channel and a D channel sent from a network terminator to an ISDN terminal equipment and using the D echo channel bit as a reception data of the layer 2 circuit. CONSTITUTION:A layer 1 circuit SINF 1 is connected to a subscriber bus 2 and a transmission/reception data of an ISDN user network interface is multiplexed and demultiplexed into two 64kbps B channel data B1, B2 and a 16kbps D channel data D. The B channel data B1, B2 are transmitted and received among the SINF 1, a telephone set via a voice circuit ALC CODEC 3, a data circuit DLC.RA and a data terminal equipment. Then the D-channel data D is transmitted/received between the SINF 1 and the layer 2 circuit LAP-D5. That is, since the data sent by the LAP-D of the title terminal equipment is received by its own equipment, the normality of the layer 1, 2 circuits is diagnosed.</p> |
