Script to dial any number using the AVM FritzBox 7360 "Wählhilfe"

dial.sh

#!/bin/bash

set -e
set -u

hostname="$1"
username="$2"
password="$3"
number="$4"

url="http://$hostname"

challenge="`curl -sS "$url"/login.lua | grep 'security:status/challenge'`"
challenge="`echo "$challenge" | cut -d'"' -f4`"

echo challenge: $challenge

# password magic. assumes there are no non-ascii characters in the password
# (avm's javascript implementation replaces all codepoints > 255 with '.')

# step 1: concat challenge and password
magic="${challenge}-${password}"

# step 2: convert everything to UTF-16 little endian and md5sum
# (md5sum needs to be done at once, since bash variables don't seem to be
#  able to hold null bytes)
magic="`echo -n "$magic" | sed 's/./\0\x00/g' | md5sum | cut -d\  -f1`"

# step 3: prepend challenge
magic="${challenge}-${magic}"

# now we should be able to login...
# (curl's -d option is completely stupid, but can be used for this, since
#  the form data probably doesn't need urlencoding. when copying code,
#  think s/-d/--data-urlencode/g)
loginpage="`curl -vsS "$url"/login.lua -d page= -d site_mode=classic -d username=$username -d response=$magic 2>&1`"
redirect="`echo "$loginpage" | grep '< Location: ' | cut -d\  -f3`"
sid="`echo "$redirect" | cut -d= -f2 | tr -d '\r'`"

echo sid: $sid

# do the dialing...
# (in case it isn't obvious: don't copy your urlencoding routines from here)
urlnumber="`echo "$number" | sed 's/ /%20/g; s/\+/%2b/g'`"
curl -sS "${url}/fon_num/fonbook_list.lua?sid=${sid}&dial=${urlnumber}&xhr=1"

echo
echo Dialing... Answer your phone.
echo To hangup, press ^D

cat

curl -sS "${url}/fon_num/fonbook_list.lua?sid=${sid}&hangup=&xhr=1"
echo

Question: I need a script to make two calls to two different internal numbers parallel (doorbell) by using the "Wählhilfe". Is this possible?