Parallel vs Serial Data Transmission

Voltage is the electrical potential difference that enables work to be done, measured in volts.

Current is the flow of electrical charge that performs work, measured in amperes or amps.

Resistance is the opposition a conductor offers to current, measured in ohms.

Ohm's Law states that the relationship between voltage, current, and resistance is Volts = Amperes x Ohms.

Capacitive and Inductive reactance are opposing forces that depend on the frequency of change.

Impedance is the opposition a conductor offers to a changing current value, measured in ohms.

American Standard Code for Information Interchange (ASCII) is a text coding that represents letters, numerals, and control actions.

ASCII was released by the U.S. government in 1963, and gradually gained acceptance due to its compatibility with various vendors.

Ethernet is a physical and signal standard that is gaining market share and acceptance in automation areas.

There are several digital communications standards used in process measurement and control, including EIA/TIA 232(F) and EIA/TIA 485(A).

The Electronic Industries Alliance (EIA) is an association of manufacturers that develops standards, and the Telecommunications Industry Association (TIA) is a subdivision of the EIA.

IBM developed the IBM 4 of 8 Code, a proprietary code that allowed error detection on a character-by-character basis in the late 1940s.

In 1963, the U.S. government released ASCII, a standard text coding, which gained widespread acceptance among vendors.

IBM also released an extended version of the 4 of 8 Code called EBCDIC, which used a cyclic redundancy check character for error detection instead of a parity bit and utilized all combinations of the 8-bit code.

EBCDIC was mathematically related to the 4 of 8 Code, but was incompatible with it and other proprietary codes.

ASCII's acceptance by the U.S. government led to its adoption by many vendors, eventually replacing proprietary codings.

The international standard for an industrial fieldbus, IEC 61158, defines eight different fieldbuses, four of which, including PROFIBUS PA and FOUNDATION Fieldbus, are primarily used in process control.

These fieldbuses are not necessarily compatible with each other, and no open, all-digital standard signal has been established as an alternative to the analog 4-20 mA signal.

Ethernet, while not a fieldbus itself, is gaining market share and acceptance in automation areas as a physical and signal standard.

Several digital communications standards are used in process measurement and control, such as EIA/TIA 232(F) and EIA/TIA 485(A).

These standards detail placing data on and removing it from the media, which is required for signaling via an electrical channel.

The IBM 4 of 8 Code, a proprietary code developed by IBM in the late 1940s, allowed for error detection on a character-by-character basis.

ASCII, a standard text coding released by the U.S. government in 1963, gained widespread acceptance among vendors due to its compatibility with various systems.

EBCDIC, an extended version of the 4 of 8 Code, was developed by IBM and utilized all combinations available to an 8-bit code by using a cyclic redundancy check character for error detection instead of a parity bit.

Proprietary codes were commonly used by manufacturers prior to the release of ASCII, but were incompatible with each other.

The EIA and TIA are associations of manufacturers that develop standards, with the TIA being a subdivision of the EIA.

The international standard for an industrial fieldbus, IEC 61158, defines eight different fieldbuses, four of which are primarily used in process control.

These fieldbuses are not necessarily compatible with each other, and no open, all-digital standard signal has been established as an alternative to the analog 4-20 mA signal.

Ethernet is a physical and signal standard that is gaining market share and acceptance in automation areas.

There are several digital communications standards, such as EIA/TIA 232(F) and EIA/TIA 485(A), used in process measurement and control.

These standards detail placing data on and removing it from the media, which is required for signaling via an electrical channel.

The IBM 4 of 8 Code, a proprietary code, was developed by IBM and allowed for error detection on a character-by-character basis.

ASCII, a standard text coding, was released by the U.S. government and gained widespread acceptance among vendors.

EBCDIC, an extension of the 4 of 8 Code, was developed by IBM and utilized all combinations available to an 8-bit code.

The EIA and TIA are associations of manufacturers that develop standards, with the TIA being a subdivision of the EIA.

The international standard for an industrial fieldbus, IEC 61158, defines eight different fieldbuses, four of which are primarily used in process control.

These fieldbuses are not necessarily compatible with each other, and no open, all-digital standard signal has been established as an alternative to the analog 4-20 mA signal.

Ethernet is a physical and signal standard that is gaining market share and acceptance in automation areas.

Several digital communications standards, such as EIA/TIA 232(F) and EIA/TIA 485(A), are used in process measurement and control.

These standards detail placing data on and removing it from the media, which is required for signaling via an electrical channel.

The IBM 4 of 8 Code, a proprietary code developed by IBM, utilized all combinations available to an 8-bit code, allowing for error detection on a character-by-character basis.

ASCII, a standard text coding, was released by the U.S. government and gained acceptance among vendors due to its compatibility with various systems.

EBCDIC, an extension of the 4 of 8 Code, utilized all combinations available to an 8-bit code, allowing for error detection through the use of a cyclic redundancy check character.

Proprietary codes, such as the IBM 4 of 8 Code, were commonly used by manufacturers prior to the release of ASCII.

The EIA and TIA are associations of manufacturers that develop standards, with the TIA being a subdivision of the EIA.

The international standard for an industrial fieldbus, IEC 61158, defines eight different fieldbuses, including PROFIBUS PA and FOUNDATION Fieldbus, which are primarily used in process control.

These fieldbuses are not necessarily compatible with each other, and no open, all-digital standard signal has been established as an alternative to the analog 4-20 mA signal.

Ethernet is a physical and signal standard that is gaining market share and acceptance in automation areas.

Several digital communications standards, such as EIA/TIA 232(F) and EIA/TIA 485(A), are used in process measurement and control.

These standards detail placing data on and removing it from the media, which is required for signaling via an electrical channel.

The IBM 4 of 8 Code, a proprietary code developed by IBM, utilized all combinations available to an 8-bit code, allowing for error detection on a character-by-character basis.

ASCII, a standard text coding, was released by the U.S. government and gained widespread acceptance among vendors due to its compatibility with various systems.

EBCDIC, an extension of the 4 of 8 Code, utilized all combinations available to an 8-bit code, allowing for error detection through the use of a cyclic redundancy check character.

Proprietary codes, such as the IBM 4 of 8 Code, were commonly used by manufacturers prior to the release of ASCII.

The EIA and TIA are associations of manufacturers that develop standards, with the TIA being a subdivision of the EIA.

The international standard for an industrial fieldbus, IEC 61158, defines eight different fieldbuses, including PROFIBUS PA and FOUNDATION Fieldbus, which are primarily used in process control.

These fieldbuses are not necessarily compatible with each other, and no open, all-digital standard signal has been established as an alternative to the analog 4-20 mA signal.

Ethernet is a physical and signal standard that is gaining market share and acceptance in

Data communications topologies are organized as point-to-point, multi-drop, or networked.

Point-to-point is a direct communication between two points, no ranking involved.

Multi-drop topology involves a master station with slave stations, or peers.

Networked topology consists of three or more stations connected by a common medium.

Modes in data communications are simplex, half-duplex, and duplex.

Simplex communication occurs only in one direction, never in the opposite.

Half-duplex communication allows for communication in either direction, but not at the same time.

Duplex communication enables simultaneous communication in both directions.

Serial transmission uses one channel, every bit following one after the other, allowing for a lower throughput compared to parallel transmission.

Parallel transmission utilizes multiple channels to transmit data and can transmit more data than serial transmission for a given message.

Parallel transmission encounters challenges such as increased equipment costs and difficulty in maintaining data reception over distance.

Cross-talk is a problem with parallel transmission that increases with signaling rate and makes obtaining a faster data rate challenging.

Serial and parallel transmission modes can be applied to point-to-point, multi-drop, and networked topologies.

The names "simplex" and "parallel" are sometimes confusing, and "unidirectional" or "full" are more descriptive alternatives.

There can be a difference between the hardware and software capabilities of a communication channel.

Names and definitions in data communications have evolved over time.