Data transmissions to and from the MS4640B conform to the protocols specified by the IEEE 488.2 GPIB Standard. The 488.2 Standard specifies how any data, such as ASCII numbers, strings, or blocks of data bytes, will be transmitted over the GPIB. This section describes the various transmission methods in use by the MS4640B. The transmission method names described below (also called notations) will be used throughout the Programming Manual when describing specific MS4640B data transfer commands. Data transmission notations are easily distinguished in text as they are always shown surrounded by the “less than” and the “greater than” characters (< >). The transmission type notations used in describing various MS4640B VNA data transmissions are:

This notation represents ASCII integer values. A comma (,) is used to separate multiple values sent in a single command's input or output string. Examples of values that can be represented by <NR1> notation:

This notation represents ASCII floating point values in decimal point format. A comma (,) is used to separate multiple values sent in a single command's input or output string. Examples of values that can be represented by <NR2> notation:

This notation represents ASCII floating point values in exponential format (scientific notation). A comma (,) is used to separate multiple values sent in a single command's input or output string. Examples of values that can be represented by <NR3> notation:

This notation is used to signify that data can be in either <NR1>, <NR2>, or <NR3> format as described above. Examples of values that can be represented by <NRf> notation:

This notation represents a string of ASCII characters (including non-printable characters) that is delimited (surrounded) with either single quotes (' ') or double quotes (" "). The string can include text formatting characters such as line feed, space, carriage return, or printer control characters. Note that if a double quote character must be sent as part of the string, then it must be followed by an additional double quote. Alternatively, the string can be sent using single quotes (See "cal_file" example below). Examples of data represented by <string> notation:

This notation represents undelimited 7-bit ASCII text. The end of the text must be terminated with the 0A character (decimal 10) and concurrent setting (^) of the GPIB End of Transmission State (EOI). This requirement makes it necessary for <Arbitrary ASCII> text to be transmitted only at the end of a program or response message, i.e., at the end of a multiple input or output statement. Example of data represented by <Arbitrary ASCII> notation:

The example shows a sample response from the *IDN?, 488.2 common query. In the example, the instrument identifies itself as an ANRITSU MS4642B, with serial number 123456, and software version 1.0 installed.

This notation represents data that is transmitted as 8-bit data bytes (00–FF hex, 0–255 decimal, notation is <DAB>). This is useful for transmitting large blocks of:

The data stream is immediately preceded by a variable length ASCII header that is encoded with the number of data bytes to be sent. The header always starts with the pound (#) character. The header and the transmitted data messages are described as follows:

Where:

Example 1 shows how 204 8-bit bytes are transmitted using the proper header. The header in this example is comprised of 5 characters (#3204). It begins with the pound character (#). The next character (3) indicates there are 3 digits to follow that indicate the number of bytes being transmitted (204). The next three characters (204) indicate the number of data bytes being transmitted immediately after the header. Next comes the actual data bytes, or information, being transmitted (<DAB1>...<DAB204>).

Example 2 shows how 12808 bytes are transmitted using the proper header. The header in this example is comprised of 7 characters (#512808). It begins with the pound character (#). The next character (5) indicates there are 5 digits to follow that indicate the number of bytes being transmitted (12808). The next five characters (12808) indicate the number of data bytes being transmitted immediately after the header. Next comes the actual data bytes, or information, being transmitted (<DAB1>...<DAB12808>).

Example 3 shows how an unknown number of bytes are transmitted using the proper header. The header in this example is comprised of 2 characters (#0). As usual, the header begins with the pound character (#). The next character (0) indicates there is an unknown number of data bytes being transmitted immediately after the header. Next comes the actual data bytes being transmitted (<DAB1>...<DABm>). The end of the data stream is signaled by sending the line feed character (0A, or decimal 10) and concurrent setting (^) of the GPIB End of Transmission State (EOI).

Character program data such as CW, FIXed, UP, and DOWN. A single instance in a command or query is <char>. If multiple instances are required, each is identified such as <char1> or <char2> and the individual elements are separated by commas:

The instrument numeric limit as the Maximum Positive/Negative Double Precision Number or:

The instrument numeric limit as the Maximum Positive/Negative Float Number or:

The instrument numeric limit as the Maximum Positive/Negative Integer or:

Three commands are provided to alter the way the arbitrary block header for output data is formed.

The following sections discuss the various data output formats:

The formats used for data transfers not involving numerical data arrays are preset. They always occur in either binary format or ASCII format, depending on the data. These data transfers include a variety of information. Examples include:

Numerical data array transfers are used to transfer the following types of data:

Each of these data transfer types are individually explained below. You can select either binary or ASCII format for data transfers involving numerical data arrays. The commands described below select and keep the format for all subsequent data transfers.

Enhanced ASCII formatting can be applied to both non-array ASCII data and numerical data arrays in the FMA format when this data is output within an <block> format. The format selectively replaces comma data element separators with a line feeds (ASCII 10) in order to enhance the visual effect. The following provides two examples of this enhanced structure: