---
name: "measerl"
section: "1"
platform: "linux"
package: "vpb-utils"
version: "4.2.61-1.4"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/measerl"
---

# measerl(1)

Measure the echo-return loss on Voicetronix telephony hardware

## NAME

measerl - Measure the echo-return loss on Voicetronix telephony hardware

## SYNOPSIS

**measerl** \[*options*\]

## DESCRIPTION

The **measerl** utility tests the echo-return loss on the phone line. For hardware that supports it, it can scan through bybrid balance register settings to help establish a lower ERL.  Having a lower ERL improves DTMF cutthrough and audio quality.  The software echo cancellation needs at least -6dB before it can make a difference.

*FXS* (station) ports should perform this test using the --nohook option with the handset already off hook and the microphone muted.

*FXO* (trunk) ports will answer to an incoming call.

A series of tones will be played down the line to determine the ERL in several parts of the audio spectrum.  You should avoid creating any other noise on the line while this test is running, or the results may be skewed.

## OPTIONS

The following options are available:

- **--help, -?**

  Show summary of options.

- **--card** number

  Explicitly select the card to test.  Default is card 0.

- **--port** number

  Explicitly select the port to test. Default is port 0 of the card being tested.

- **--nohook**

  Use this option for testing station (FXS) ports.

- **--offhook**

  Take an FXO port off hook immediately.  Don't wait for an incoming ring.

- **--bal1** value

  - **--bal2** value

  - **--bal3** value

  Set codec hybrid balance registers.  Only for hardware which explicitly supports that.

- **--ec**

  Enable the echo canceller.

- **--pg** gain

  Set codec play gain.  Values may range from -12.0 to 12.0.

- **--rg** gain

  Set codec record gain.  Values may range from -12.0 to 12.0.

- **--dial** port

  Dial out another port on the same card.

- **--dial** port number

  Dial *number* from *port* on the same card.

- **--scan** file start end step

  Scan the hybrid balance register settings from *start* to *end* in increments of *step*, recording the results to *file*.  Only for hardware that explicitly permits setting these registers.  Valid values for the start and end are in the range 0 - 255.

- **--autoscan**

  Automatically scan the codec balance values.

- **--handset**

  Proto handset mode.

- **--loop**

  Enable software loopback.

- **--hostecho**

  Enable the host based echo canceller.

## SEE ALSO

[**vpbecho**(1)](/vpbecho/1.md), [**ringstat**(1)](/ringstat/1.md)

## AUTHOR

Ron Lee, Peter Wintulich, David Rowe, Voicetronix \<support@voicetronix.com.au\>

This manual page was written by Ron \<ron@debian.org\>, for the Debian project (but may be used by others).