Backplane-interface bus

The simplest way (as seen from the view of the electronic circuit designer) to route the acquired data into computer memory is via a direct bus interface. This method is very powerful because it allows very fast acquisition of data. Nevertheless the 

When using a RS-232 interface one has to bear in mind that the transmission rates are restricted to about 1 kbyte/second. On the other hand it is possible to transmit data over very long distances (round the world) by using a modem if low data rates (100 bytes/second) are sufficient. 

The IEEE-488 standard is a widely accepted standard of data transmission between laboratory equipment. Data are transferred in a parallel way. The IEEE-488 bus is very sophisticated and flexible. It is sometimes called General purpose interface 

The IEEE-488 has one major drawback in everyday applications. The overall performance of the bus depends on the slowest device connected to the bus, which means that one slow instrument can slow down data transfer rates within a system to a not acceptable level (e. g. think of a hard disk which is connected to the computer on the same bus). 

A lot of software products are available in order to perform data acquisition and/or data manipulation. Most of the packages are specific to the interface card used and most of them are only a collection of subroutines which allow to control the specific hardware. 

---