# Echo.AutoSwitchingRefSource

Determines if the on-board switching manager performs automatic switching of the echo canceller reference stream.

#### Syntax

Echo.AutoSwitchingRefSource = setting

#### Access

Read/Write

#### Type

String

#### Default

NO

#### Allowed values

NO | YES

#### Example

Echo.AutoSwitchingRefSource = NO

#### Details

Echo.EnableExternalPins must be set to YES to use the Echo.AutoSwitchingRefSource keyword.

Automatic switching occurs when a connection is made to a line from another line (or any other source) and when the destination line is also connected to a DSP that has echo cancellation enabled.

For example, using swish:

swish> openswitch b = agsw 0
swish> makeconnection b local:0:0 to local:17:0 # line 0 to DSP
swish> makeconnection b local:0:0 to local:1:1 duplex # line 0 to/from line 1

The first connection connects DSP 0 to listen to line 0.

The second connection connects lines 0 and 1 together. The remote parties on line 0 and line 1 are able to talk to each other. DSP 0 is still monitoring line 0. This configuration is referred to as tromboning.

The switching manager automatically makes the following connection:

local:0:1 --> local:35:0

This connects line 1 to the echo canceller reference. It enables cancellation of echoes that occur on line 0 from energy originating on line 1.

#### See also

Echo.EnableExternalPins