ITU-T X.42

This Recommendation defines procedures and a framework for providing access to a Public Data Network (PDN) by a DTE operating under the control of a generalized polling protocol, via the use of a Packet Assembly/Disassembly (PAD) device situated within (or associated with) the PDN. The PAD supporting the generalized polling protocol aspect is referred to as a GPAD. The generalized polling environment provides support for access, along with basic requirements necessary within the PAD to enable the selection and modification of the protocol Aspect. This Recommendation has been developed in realization that a well-established base of DTEs operating under control of a generalized polled protocol needs to access a PDN. Also, procedures are defined that allow Internet Protocol (IP) enabled devices to access their corresponding networks over the generalized polling protocol defined under ITU-T Rec. X.42. The revision is a result of comments received from implementers. Several clarifications are introduced that remove ambiguities in the areas of bit, field and frame sequencing; event conditions; and checksum algorithms.