What is an Address in Communication Systems?
It should be called as designator for the location of data in a storage device; allows the retrieval of data by reading the contents of a specific location. Also, the identity of a peripheral device. These (normally unique) allow individual devices on a single communications line to recognize and respond to messages directed at them.
What do you mean by ARP?
APR stands for address resolution protocol. A transmission control protocol/internet protocol (TCP/IP) process that maps an ID address to an Ethernet address; required by TCP/IP for use with
Ethernet.
What is the role of ARQ in data transmission?
Automatic request for transmission. A request by the receiver for the transmitter to retransmit a
block or a frame because of errors detected in the originally received message.
What is ASCII standard ?
American Standard Code for Information Interchange. A universal standard for encoding
alphanumeric characters into 7 or 8 binary bits. Drawn up by ANSI to ensure compatibility
between different computer systems.
What do you mean by asynchronous Communications?
Communications in which characters can be transmitted at an arbitrary, unsynchronized time,
and where the time intervals between transmitted characters may be of varying lengths.
Communication is controlled by start and stop bits at the beginning and end of each character.
What is bandwidth in communication?
The range of frequencies available, expressed as the difference between the highest and lowest
frequencies, in hertz (cycles per second, abbreviated Hz).
What does band pass filter do?
A filter that allows only a fixed range of frequencies to pass through. All other frequencies
outside this range (or band) are sharply reduced in magnitude.
Unit Baud describes what?
Unit of signaling speed derived from the number of events per second (normally bits per second).
However, if each event has more than one bit associated with it, the baud rate and bits per second are not equal.
What are system BIOS?
The basic input/output system for the computer, usually firmware-based. This program handles
the interface with the PC hardware and isolates the operating software (OS) from the low-level
activities of the hardware. As a result, application software becomes more independent of the particular specifications of the hardware on which it runs, and hence more portable.
Differentiate between bits & bytes?
One bit is one binary digit,either a binary 0 or 1. One byte is the amount of memory needed to store
each character of information (text or numbers). There are eight bits to one byte (or character),
and there are 1024 bytes to one kilobyte (KB). There are 1024 kilobytes to one megabyte (MB).
Data acquisition boards typically take 2-byte samples; a board acquiring data at a 20 kHz
sample rate is actually gathering 40,000 bytes of data per second.
What is the purpose of buffer in electrical transmissions?
An intermediate temporary storage device used to compensate for a difference in data rate and data
flow between two devices (also called a spooler for interfacing a computer and a printer).
What is the significance of the terminology bus in communications?
A data path shared by many devices, with one or more conductors for transmitting signals, data or
power. Also, the expansion connector built into a computer. Boards are inserted into this connector,
and all communication between the computer and the board occurs through the computer’s bus.
What is cache memory?
A fast buffer memory that fits between the CPU and the slower main memory to speed up CPU
requests for data.
What is clock pulse?
A rising edge, then a falling edge (in that order), such as applied to the clock input of an 8254
timer/counter.
What is CMRR?
Common mode rejection ratio – A board’s ability to measure only the voltage difference between the leads of a transducer, rejecting what the leads have in common. The higher the CMRR, the
better the accuracy.
What does counter data register do?
The 8-bit register of a (8254 chip) timer/counter that corresponds to one of the two bytes in the
counter’s output latch for read operations and count register for write operations.
What is CRC error detection method in communications?
Cyclic redundancy check. A basic error checking mechanism using a polynomial algorithm based
on the content of the frame and then matched with the result that is performed by the transmitter
and included in a field appended to the frame. Also referred to as CRC-16 or CRC-CCITT.
What does the term CSMA/CD defines?
Carrier sense multiple access/collision detection. When two stations transmit at the same time on a
local area network, they both cease transmission and signal that a collision has occurred. Each then
retries again after waiting for a random time period.
