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.TH MEASERL 1 "Jan 4, 2007" "VPB driver package" "Voicetronix Telephony Tools"
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.SH NAME
measerl \- Measure the echo-return loss on Voicetronix telephony hardware
.SH SYNOPSIS
.B measerl
.RI [ options ]
.SH DESCRIPTION
The \fBmeaserl\fP 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.
.PP
\fIFXS\fP (station) ports should perform this test using the \-\-nohook option
with the handset already off hook and the microphone muted.
.PP
\fIFXO\fP (trunk) ports will answer to an incoming call.
.PP
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.

.SH OPTIONS
The following options are available:
.TP
.B \-\-help, \-?
Show summary of options.
.TP
.BR \-\-card " number"
Explicitly select the card to test.  Default is card 0.
.TP
.BR \-\-port " number"
Explicitly select the port to test. Default is port 0 of the card being tested.
.TP
.B \-\-nohook
Use this option for testing station (FXS) ports.
.TP
.B \-\-offhook
Take an FXO port off hook immediately.  Don't wait for an incoming ring.
.TP
.BR \-\-bal1 " value"
.TP
.BR \-\-bal2 " value"
.TP
.BR \-\-bal3 " value"
Set codec hybrid balance registers.  Only for hardware which explicitly supports that.
.TP
.B \-\-ec
Enable the echo canceller.
.TP
.BR \-\-pg " gain"
Set codec play gain.  Values may range from -12.0 to 12.0.
.TP
.BR \-\-rg " gain"
Set codec record gain.  Values may range from -12.0 to 12.0.
.TP
.BR \-\-dial " port"
Dial out another port on the same card.
.TP
.BR \-\-dial " port number"
Dial \fInumber\fP from \fIport\fP on the same card.
.TP
.BR \-\-scan " file start end step"
Scan the hybrid balance register settings from \fIstart\fP to \fIend\fP in
increments of \fIstep\fP, recording the results to \fIfile\fP.  Only for
hardware that explicitly permits setting these registers.  Valid values for
the start and end are in the range 0 - 255.
.TP
.B \-\-autoscan
Automatically scan the codec balance values.
.TP
.B \-\-handset
Proto handset mode.
.TP
.B \-\-loop
Enable software loopback.
.TP
.B \-\-hostecho
Enable the host based echo canceller.

.SH SEE ALSO
.BR vpbecho (1),
.BR ringstat (1)
.SH AUTHOR
Ron Lee,
Peter Wintulich,
David Rowe,
Voicetronix <support@voicetronix.com.au>
.PP
This manual page was written by Ron <ron@debian.org>,
for the Debian project (but may be used by others).