FND Enterprises

One of the great features of the Grandstream GXP-2000 VoIP phone is that you can create and upload custom ring tones to your phone. The sad part is that the utility to do so on their web site only exists for Solaris and Linux.

This article will show you how to create compatible ringer files using an open-source utility called SoX. Mac OSX users can download a version of SoX here. You’ll also need this Perl script:

#!/usr/bin/perl
#——————————————————————————
# Create ringtone file for Grandstream BT100 phone, using uLaw input.
#
# Author: Tony Mountifield
# Date: 28 May 2004
# File: makering.pl
# History:
# 28/05/2004 Initial version.
# 29/05/2004 Added checks for input file size being even and not too large.
# 30/05/2004 Phone will not accept files larger than 65536 bytes.
# 06/06/2004 Modified for the 1.05.00 firmware, probably doesn’t support
# older firmware any longer
#——————————————————————————
#
# Usage:
# Use sox to convert any audio input file to uLaw and pipe to this prog, e.g.
#
# sox inputfile -r 8000 -c 1 -t ul - rate | makering.pl ring1.bin
#
# (try using /usr/share/sounds/phone.wav for the inputfile)
#
# Check the output file by using the following command:
#
# tail +513c ring1.bin | play -t ul -
#
# Finally, put the ring file in /tftpboot on the phone’s TFTP server,
# and reboot the phone.
#
#——————————————————————————
#
# Credits:
# Based on analysis by Stephen R. Besch
#
# Copyright: placed into the public domain by the author
#
# Warranty: none!
#
#——————————————————————————

$filename = shift or die “need output filename\n”;

undef $/; # slurp whole file at once…

$audio = <>; # … like this

$filesize = 512 + length $audio;

if ($filesize & 1) {
# length odd, add a zero byte (should never happen)
$audio .= chr(0);
}

if ($filesize >= (2 * 65536)) {
print STDERR “Warning: $filesize is bigger than 2 bytes, trouble may be ahead.”
}

# this is the format for the header
$headerfmt = “N n C4 n C C C C a16 C C x4 n n x214 n n N x72 a176″;

# get the current date and time
($min, $hour, $day, $month, $year) = (localtime)[1..5];
$year += 1900;
$month += 1;

# create the header, with zero for the checksum
$header = pack $headerfmt,
$filesize/2, # 00 - filesize/2
# FIXME: I’m guessing that the 0000 we
# always see at the beginning of
# the files are an extended file size
0, # 04 - put checksum in later
1,0,0,1, # 06 - version
$year, # 0a - year
$month, # 0c - month
$day, # 0d - day
$hour, # 0e - hour
$min, # 0f - min
“ring.bin”, # 10 - name, seems to always be ring.bin
# FIXME: Assumption 1: always ring.bin
# FIXME: Assumption 2: name field is 16 chars
0, # 20 - ?
0, # 21 - ? 0 (ring1.bin) or 9 (ring2.bin) - Codec?
# 22 - 4 NULL bytes, unknown
0xc8, # 26 - ? 00C8 (0 sometimes seen before)
0, # 28 - 0000 (ring2.bin) or 0001 (ring1.bin) - why?
# 2a - 214 null bytes
0, # 100 - ? 0
256, # 102 - ? 0×0100
$filesize/2, # 104 -
# Next comes an array of positions, which seems
# to be a sort of ‘play until’ set of instructions
# 150 - Description
“Grandstream standard music ring”;

# sanity check
$headerlen = length $header;
die “header length wrong ($headerlen)\n” unless $headerlen == 512;

# add the audio
$header .= $audio;

# compute the checksum
$checksum = unpack “%16n*”, $header;
printf “checksum before = %04x\n”, $checksum;

# insert it in the correct place
substr($header,4,2) = pack “n”,-$checksum;

# ensure the new checksum is zero
$checksum = unpack “%16n*”, $header;
printf “checksum after = %04x\n”, $checksum;
die “checksum failed\n” unless $checksum == 0;

# write the file
open F, “>$filename” or die “can’t open output file $filename: $!\n”;
print F $header;
close F;

# end

Just like the script instructions say, you execute the following command:

sox inputfile -r 8000 -c 1 -t ul - rate | makering.pl outputfile

Depending on your system configuration, you might have to use this:

sox inputfile -r 8000 -c 1 -t ul - rate | perl makering.pl outputfile

That’s all! SoX converts your file to the proper format and the Perl script modifies the file header information to be acceptable to the Grandstream phone. Your output files must be named ring1.bin, ring2.bin, or ring3.bin. The file name will replace that particular custom ring tone in the telephone when uploaded.

To upload the files to your phone, simply place them in the HTTP or TFTP directory your phone updates and proceed with a normal firmware update process.

Here are some sample ringers that I converted for you to try out:

Horse - the sound of a horse neighing

Owl - the hooting of an owl. I wonder hoo could be calling?

Bell Ringer 1 - an old style telephone ringer

Bell Ringer 2 - another old style bell ringer

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