Some audio cards have great number and types of connectors: inputs and outputs.
Inputs and outputs intend for:
- input/output analog and digital audio signals;
- control and synchronization several audio devices.
The beginning of articles about sound cards here...
Often single connector provides connection to one input or output of sound card. However, the number of connectors does not always match the number of inputs and/or outputs, are visible to the operating system or in the settings of music editor (DAW).
As example, physical input can be switched between input line and microphone circuits. You can't write microphone and line-in simultaneously.
|TRS 1/4", jack||Professional connector|
|TRS 1/8", jack||Portable audio, computer sound devices for beginers|
|XLR||Professional connector (some has lock)|
- XLR (professional microphone)
- TRS (Jack 1/4 "- for guitar input or line input/output).
This connector is used to save space and allows connect or microphone, or synthesizer, or guitar.
Professional connectors have more robust joint (mechanical and electrical). Sometime with locks or threading.
Analog inputs and outputs may be balanced (symmetrical) or unbalanced (not symmetrical). Balanced inputs are less susceptible to interference than not balanced. Balanced inputs give less noise on the record.
Schemes of balanced and unbalanced cables here...
Read what is analog input here...