# Short or Long Forms

SCPI Basics

- Program Message Terminator
- Short or Long Forms
- White Space
- Combining Commands
- Adding Parameters to a Command
- String Arguments
- Numbers
- Infinity Representation
- Queries
- Endianness of Returned Binary Block Data
- NaN (Not A Number)
- Sequential and Overlapped Commands
- SCPI Tree

Commands and queries may be sent in either long form (complete spelling) or short form (abbreviated spelling). The description for each command shows both versions; the extra characters for the long form are shown in lowercase. However, commands can be sent using any combination of uppercase or lowercase ASCII characters. Responses, however, are always returned in uppercase. Programs written in long form are easily read and are almost self-documenting. Using short form commands conserves the amount of controller memory needed for program storage and reduces the amount of I/O activity.

The short form is the first four characters of the keyword, unless the fourth character is a vowel. Then the mnemonic is the first three characters of the keyword. If the length of the keyword is four characters or less, this rule does not apply, and the short form is the same as the long form. For example:

    :TIMebase:POSition 1E-6

is the long form, and

    :TIM:POS 1E-6

is the short form.

Examples of Long and Short Command Form Rules
Long Form | Short Form | How the Rule is Applied
--- | --- | ---
BRATe | BRAT | Short form is the first four characters of the keyword.
DELay | DEL | Fourth character is a vowel, short form is the first three characters.
PATTern | PATT | Short form is the first four characters of the keyword.
DISK | DISK | Short form is the same as the long form.
SAVE | SAVE | Short form is the same as the long form.