GPIO Operation

Overview

The GPIO function (General Purpose Input/Output) provides easy interconnection of logic and control with simple switches, indicators, and equipment provided by other manufacturers. This is not limited to intercom equipment, and in practice will most likely include a mix of audio, video, intercom, or other types of equipment.

Dashboard provides advanced functions to the user, such as on/off delay timers and in-depth logic control and nesting/layering of functions.

Each Telos Infinity device supporting GPIO’s is detailed in this manual under the relevant section.

Signal Description

For background information, the following describes the terminology used in this manual.

GPIO Logic Levels

The following signal levels are defined for the GPIO system. These levels are consistent within the Telos Alliance products and with industry standards.

Mode	Logic Level	State
Normal	Low	Active/Asserted
Normal	High	Inactive/De-Asserted
Inverted	Low	Inactive/De-Asserted
Inverted	High	Active/Asserted

GPIO Signal Behaviors

The following table provides an overview of the different signal behaviors used by the GPIO functions.

Type	Mode	Notes
GPI	Normal (Momentary)	Default behavior is momentary (function is only active while the GPI is asserted)
GPI	Latching	Function latches "on" until a different stimulus disables the chosen function
GPI	Toggle	Function latches "on" until the same GPI is again asserted to disable the chosen function
GPO	Normal (Momentary)	Default behavior is momentary (GPO is asserted only when the function is active)
GPO	Latching	GPO asserts until a different stimulus de-asserts it
GPO	Toggle	GPO asserts until the same system function de-asserts it
GPO	Pulse	GPO asserts for a specified amount of time and then de-asserts itself

GPIO Logic States

The following table provides an overview of the different signal logic states used by the GPIO functions.

Type	Mode	Logic Level	State	Notes
GPI	Normal	Low	Active/Asserted	Default system behavior is Active Low for GPIs
GPI	Normal	High	Inactive/De-Asserted
GPI	Inverted	Low	Inactive/De-Asserted
GPI	Inverted	High	Active/Asserted
GPO	Normal	Low	Active/Asserted	Default system behavior is Active Low for GPOs
GPO	Normal	High	Inactive/De-Asserted
GPO	Inverted	Low	Inactive/De-Asserted
GPO	Inverted	High	Active/Asserted