Automated call attendant with call blocking and voice messaging on a Raspberry Pi.
The Call Attendant (callattendant) is a python-based, automated call attendant that runs on a lightweight Raspberry Pi or other Linux-based system. Coupled with a modem, it provides a call blocker and voice messaging system that can screen callers and block robocall and scams from your landline.
Features being developed include:
- A call blocker that intercepts robocallers and blocked numbers at or before the first ring
- Permitted numbers pass straight through to the local phone system for normal call ringing and answering
- Visual indicators to show whether the incoming call is from a permitted, blocked, or unknown number
- Call details, permitted numbers, and blocked numbers are available in a web-based user interface
- Blocked callers are handled by a voice messaging system that requires human interaction, e.g, "Press 1 to leave a message"
- Raspberry Pi 3B+ or better
- US Robotics 5637 Modem
Call history, permitted numbers, blocked numbers and caller management is all performed through a web interface.
The Call Attendant project was inspired by the pamapa/callblocker project, an excellent Raspberry Pi based call blocker. However, the callattendant differs from the callblocker in that adds voice messaging; and the callattendant is written entirely in Python, uses SQLite for the call logging, and implments the web interface with Flask.
The following blogs from IoT Bytes by Pradeep Singh were very useful for learning to how to program the Raspberry Pi and the US Robotics 5637 modem. His blog site has many Raspberry Pi resources. Thanks Pradeep!
- Incoming Call Details Logger with Raspberry Pi
- Play Audio File on Phone Line with Raspberry Pi
- Record Audio from Phone Line with Raspberry Pi
The development plan's phase objectives are captured in the GitHub projects.
- Iteration #I1: v0.1
- Iteration #E1: v0.2
- Iteration #T1: v1.0
You will need a Raspberry Pi running Raspbian or better and access to the Internet for the software installation. For the project, you will need a modem of some sort to do the telephony communications.
The U.S. Robotics USR5637 56K USB Modem:
https://www.amazon.com/gp/product/B0013FDLM0/ref=ppx_yo_dt_b_asin_image_o03_s00?ie=UTF8&psc=1
has been proven effective. For some installs, it just works, no config needed. It showed up as /dev/ttyACM0.
You need a copy of this repository placed in a folder on your pi, e.g., /pi/home/callattendant.
You can either clone this repository, or download a zip file,
or download a specific release from Releases.
Here's how clone the repository with git into your home folder:
cd
git clone https://github.com/emxsys/callattendant.git
cd callattendantIf you download the latest code or a
specific release, the unzpped folder will be named callattendant-master or callattendant-<release_tag>
depending on what you downloaded. You can rename it if you wish. Here's how unzip it into your home folder.
cd
unzip ~/Downloads/callattendant-master.zip
cd callattendant-masterThe installation calls for Python3.X.
For development purposes, you might be best served by setting up a virtual environment. If you intend to simply install and run the callattendant on a dedicated Raspberry Pi, you can skip this step and proceed with Install Packages.
The following instructions create a virtual environment named python3 within the current folder:
sudo apt install virtualenv
virtualenv python3 --python=python3
source python3/bin/activateNow you're operating with a virtual Python. To check, issue the following command:
$ which pythonYou should see output of the form:
(python3) pi@raspberryi:~/testing $ which python
/home/pi/testing/python3/bin/python
To make sure you're on 3.x as requested, issue:
$ python --versionYou should see output of the form:
(python3) pi@raspberrypi:~/testing $ python --version
Python 3.7.3
We've provided a requirements file called requirements.txt. Let's use it to
install the required packages. But first, navigate to the folder where the
callattendant repository was placed, e.g., /pi/home/callattendant.
$ pip install -r requirements.txtIn my install, lxml took a long time to build (because Raspberry Pi) but it's worth the wait to get to that part of blocking spam calls. So chill and do whatever it is you do while software builds.
In the callattendant/src directory, issue the following command:
python callattendant.pyYou should see output of the form:
(python3) pi@raspberrypi:~/testing/callattendant/src $ python callattendant.py
CallLogger initialized
Blacklist initialized
Whitelist initialized
AT+FCLASS=8
OK
Modem COM Port is: /dev/ttyACM0
AT
OK
ATZ3
OK
ATV1
OK
ATE1
OK
AT+VCID=1
OK
ATI4
* Serving Flask app "userinterface.webapp" (lazy loading)
* Environment: production
WARNING: This is a development server. Do not use it in a production deployment.
Use a production WSGI server instead.
* Debug mode: off
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
----Option----- --Setting-- Cmd ----Option----- --Setting-- --Cmd--
Comm Standard CCITT B0 Answer Ring# 0 S0=000
Command Echo Enabled E1 Escape Char 43 S2=043
Speaker Volume Medium L2 CR Char 13 S3=013
Speaker Control OnUntilCD M1 LF Char 10 S4=010
Result Codes Enabled Q0 BS Char 8 S5=008
Dialer Type Tone T/P Dial Pause 3 sec S6=003
Result Form Text V1 NoAns Timeout 60 sec S7=060
Extend Result Enabled X4 "," Pause 2 sec S8=002
DialTone Detect Disabled X4 No CD Disc 2000 msec S10=020
BusyTone Detect Disabled X4 DTMF Speed 95 msec S11=095
DCD Action Std RS232 &C1 Esc GuardTime 1000 msec S12=050
DTR Action Std RS232 &D2 Calling Tone Enabled S35=001
V22b Guard Tone Disabled &G0 Line Rate 33600 S37=000
Flow Control Disabled &H0
Error Control V42,MNP,Bfr &M4
Compression 44 42b MNP5 &K1
OK
Navigate to <pi_address> on port 5000 and you should see the home page. Make a few calls to yourself to test the service.
We're going to define a service to automatically run the Call Attendant on the Raspberry Pi at start up. Our simple service will run the callattendant.py script and if by any means is aborted it is going to be restarted automatically.
The service definition must be on the /lib/systemd/system folder. Our service is going to be called "callattendant.service":
cd /lib/systemd/system/
sudo nano callattendant.serviceCopy the following text into the callattendant.service unit file, using your path to callattendant.py:
[Unit]
Description=Call Attendant
After=multi-user.target
[Service]
Type=simple
ExecStart=/usr/bin/python /home/pi/callattendant/src/callattendant.py
WorkingDirectory=/home/pi/callattendant/src
Restart=on-abort
[Install]
WantedBy=multi-user.target
You can check more on service's options in the next wiki: https://wiki.archlinux.org/index.php/systemd.
Now that we have our service we need to activate it:
sudo chmod 644 /lib/systemd/system/callattendant.service
chmod +x /home/pi/callattendant/src/callattendant.py
sudo systemctl daemon-reload
sudo systemctl enable callattendant.service
sudo systemctl start callattendant.serviceFor every change that we do on the /lib/systemd/system folder we need to execute a
daemon-reload (third line of previous code).
You can execute the following commands as needed to check the status, start and stop the service, or check the logs. Several shell scripts are included in the root of this project to perfom these tasks.
sudo systemctl status callattendant.service
sudo systemctl start callattendant.service
sudo systemctl stop callattendant.service
sudo journalctl -f -u callattendant.service
A few web pages are used to monitor your installation. You can use localhost for the pi_address
when you are running the web browser on the pi.
The call log displays all the calls that have been processed by the call attendant. This list refreshes automatically after a period of several minutes.
http://localhost:5000/
This is the list of blocked numbers.
http://localhost:5000/blocked
This is the list of permitted numbers.
http://localhost:5000/permitted
If needed, you can use DB Browser for SQLite to view and edit the tables used by the callattendant.
sudo apt-get install sqlitebrowser
sqlitebrowser callattendant/src/callattendant.db