1

Scope

1.1

This International Standard specifies the medium characteristics for

- twisted pair multipoint interconnections in either 2-wire or 4-wire network topology in order to provide for half duplex or duplex data transmission capability, respectively; - a binary and bi-directional signal transfer of the interconnected endpoint systems; - the electrical and mechanical design of the endpoint system branch cables and the common trunk cable, which may be up to 1 200 m in length; - the component measurements of the integrated circuit type generators and receivers within the endpoint systems; - the applicable data signalling rate up to 12,5 Mbit/s.

1.2

The defined electrical component characteristics and measurements are in close conformance with the twisted pair point-to-point characteristics given in ITU-T Recommendation V.11.

1.3

This International Standard does not describe a complete physical interface and has no functional interface characteristics, such as

- number of interchange data and control circuits; - type, size and pin allocation of the endpoint system and branch trunk cable connectors; - data and control signal encoding; - time relations between signals on the interchange circuits; - mode of synchronous or asynchronous transmission; - signal quality for transmission and reception.

1.4

This International Standard does not specify special environme ntal conditions, such as galvanic isolation, electromagnetic interference (EMI), radio frequency interference (RFI), and human safety. This may form the subject of a future amendment.

1.5

This International Standard is primarily a component specification. It is not sufficiently specified for satisfactory interoperation in all possible configurations. It is the responsibility of implementors to ensure that their intended configurat ion will allow satisfactory interoperation.

1.6

This International Standard may be combined with any appropriate set of functional and additional environmental characteristics so as to meet the practical data transmission requirements in the field of local or wide area networks.