IEEE 1615:2007 pdf free download – IEEE Recommended Practice for Network Communication in Electric Power Substations
The protocol-independent converter is sometimes called a “terminal server””(also known as a “port server”)in traditional information systems and typically supports from l to 16 serial ports.It is used when bothpieces of equipment to be interfaced understand the same protocol,，and merely requires a physicalconversion of network packets to/from a serial data stream (usually RS232 or RS485).
A protocol-specific converter is used when two pieces of equipment cannot communicate because they usedifferent protocols.This is a more sophisticated device than the protocol-independent converter in terms ofhow each interface is handled and the amount of configuration required. Some devices translate requestsand responses on Protocol 1 directly to/from Protocol 2. A prerequisite for this design is a one-to-onemapping between requests and data types of the two protocols. More often, devices let both protocols runseparately. Data and control are stored in a generic format, and converted by the protocols as appropriate.This type of design requires much more configuration information.
4.3.3 Converting from analog leased to digital leased lines
Some utilities have relied on leased communication lines from a telecommunication service company(Telco) provider. In many cases, the utilities did so with the belief that the line was dedicated, end-to-end,to the sole function of their use. These lines handled analog signals.
Analog lines are disappearing in the Telco world. A solid copper wire pair connecting two pointsdisappeared years ago. The copper pair delivered to the utility is really just wires to the nearest ‘Telconetwork center. From that point forward, the traffic on the wires becomes digital signals through the Telconetwork. The Telco performs the A-to-D and D-to-A conversion and reserves a packet connection for thattraffic. So for all practical purposes, the connection is permanent and essentially private.
Telcos charge different rates for digital service. For the equivalent of an analog leased line, 56 kb/s, theycharge a higher base rate;however,they charge only for the distance to the nearest Telco digital hub.Where the utility pays the end-to-end distance charges for an analog line, it will pay a lesser distancecharge for digital line, potentially saving the utility Telco charges.Note this assumes the utility has alreadyinstalled any required Telco isolation equipment.Should a line that is not equipped with isolation beconverted, it loses its “grandfathered”status and would need to be equipped for isolation at utility expense.
The IPS is composed of several protocols that provide data transport services and a number of applicationsfor network-related activities. It is commonly referred to“TCP/IP,” after the two most important protocolsin it: the transmission control protocol (TCP) and the Internet protocol (IP), which were also the first twodefined.However, the IPS refers to the entire set of protocols developed by the Internet community.TheInternet protocols are defined by request for comment (RFC) documents available from the InternetEngineering Task Force (IETF)*as public domain works. Although some of the RFCs specify the Internetprotocols, many of the RFCs are for information or application guidance only and are not official standards.while the lPs can be roughly fitted to the open systems interconnection (OSI) model that describes a fixedset of seven layers and some vendors like to use this model, some believe that fitting the lPS to the OSImodel does more to confuse than to help. Note that the IPS does not define the data link and physical layerbecause the IPS was designed to accommodate any underlying network technology.