Abstract: A packet switched network has a system for providing an end-to-end connection for a communication or data transfer session between a host processor and a transparent connection device, which may be an unattended device, both utilizing a 3270 protocol. A terminal PAD is responsive to positive dataset signals on the associated line for the device indicating desire to establish communication by the device, irrespective of the absence of polling of the device by the host or by the terminal PAD, to transmit a call request packet through the network to a host PAD operatively associated with the host. The host PAD is responsive to the call request subsequent to a poll from the host to transmit call accept and circuit enable packets through the network to the terminal PAD. The latter then commences polling of the device to evoke information and data messages from the device for end-to-end communication with the host in the data transfer state.

Abstract: A data communications system has a layered communication architecture including network services protocols including a link layer and higher level protocols, and has IBM or IBM-compatible synchronous data link control (SDLC) devices including a host computer and a plurality of end user devices desiring to communicate across an X.25 packet-switching network (PSN) of the communications system. A packet assembler/disassembler (PAD) support X.25 communication across the PSN between the SDLC-utilizing host computer and the SDLC-utilizing end user device. In one embodiment, separate high level data link control (HDLC) PADs are provided at each end of the PSN operationally associated with the host computer and the plurality of end user devices, respectively.