| 摘要 |
<p>PURPOSE:To make data communication not influenced by virtual call disconnection due to a trouble in a packet exchange network possible by executing setting of virtual call and resending of data by a protocol conversion communication device provided between a terminal and a packet exchange network. CONSTITUTION:An I frame 401 transmitted from a host computer is converted to a data packet 402 of D(S)=1 in a protocol converting device A and transmitted to a packet exchange network. In the case where trouble occures in the network and virtual call is cut off while the data packet is being transferred in the packet exchange network, the data packet is abandoned without sending to a protocol converting device B. When virtual call and resetting are made thereafter, protocol converting devices A and B transmits internal control data packet that makes receiving frame system number D(R) controlled by an additional sequence number controlling device user data to an objective protocol converting device.</p> |
