Houston App: System overview

Houston, is a mobile application replacing the radio communication system previously used by the Transports Publics Fribourgeois (TPF). Houston is a system using existing data network.

The system is spread over more than 200 busses, 30 team leaders and the operation center. It covers the needs of three types of users: the operators, the bus drivers and the team leaders (Houston: a mobile app to replace a radio communication system).

The major components

So how’s Houston working? Here is an overview of the major components. Houston is a distributed system composed of:

  • Two Mobile Apps that fulfill the specific need of bus drivers and team leaders
  • A Web Client used by the operators to create any type of call
  • A Cloud Communication Platform to establish Voice over IP (VoIP) and standard phone call over the Public Switch Telephone Network (PSTN) without having to deal with the complexity of building and maintaining a communication infrastructure. The cloud platform used in this system is Twilio (more details on that later)
  • A Public API: implemented by a backend server used as a bridge between mobile apps, web clients and Twilio. It is connected to a database that stores user identities and bus planning. The database also keeps traces of all performed calls.

A deeper look inside each component of the system and how each of them interacts together will help to understand why Houston was a huge challenge.

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Houston: a mobile app to replace a radio communication system

Bring your company radio system to the 21st century using VoIP and mobile applications to improve communication quality while reducing costs.

With the project Houston, we took the challenge of replacing the old radio network of the Transports Publics Fribourgeois (TPF), a swiss public transportation company by a system using existing data network and running on mobile applications. This solution solved the problem of maintaining a dedicated radio network. It also improved both the global quality of the communication and the availability of the system.

Initial situation: communication based on radio system

Since decades, employees of the Transports Publics Fribourgeois (TPF) have been using standard radio to communicate between them. The radio system is meant to cover the needs of the users. It is spread over more than 200 busses, 30 team leaders and the operation center). There are three types of users, with specific needs:

  • The operators – working in the operation center – use the radio to speak to a specific bus driver, or to broadcast messages to all or part of the running busses.
  • The team leaders are dispatched at different locations. They use the radio to manage daily events – such as the replacement of a driver – or to inform many drivers of a change in the network – for example in case of an accident.
  • The bus drivers use the bus radio as the main means of communication while driving. They can call other busses, the team leaders or the operation center.


Logo TPF

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Good vibes at DjangoCon Europe 2015


Last year’s DjangoCon Europe took place on its own island, and this time we were welcomed by the beautiful Cardiff University. One of the goals the organizers immediately set was to promote diversity and embrace minorities, encouraging them to participate to this event. I remember when I bought my ticket and I read “all dietary requirements can be met” and I thought “they’re probably trying to set the bar too high”. This is a not so unusual statement, but when confronted to reality you usually end up with dishes not adapted to your dietary requirements, and, as a minority, having to ask for something special can really make you feel excluded. This time was different, as the organizers meticulously took care of that.

I talked about dietary requirements because it’s an important topic for me, but they also made sure to have a code of conduct, a financial assistance for people who want but can’t afford to attend, a wellbeing service, a subscription system for meals to avoid wasting food, reusable aluminum bottles instead of plastic water bottles, live transcription of talks (for hard of hearing or non-english people), and even a crèche.

All of this was not just buzzwords but was carefully handled by the organizers. In the end, it made everyone feel welcome and put a very warm atmosphere to the event. Talking with people was very interesting and rewarding because of the incredible diversity of backgrounds. A few days after the conference the Django Software Foundation even released a diversity statement to make sure everyone feels welcome in the Django community.

The choice of talks was about 50/50 between technical talks and community talks. I found the community talks to be very inspiring such as Ola Sendecka’s “Into the rabbit hole” which reminded me the benefits of the Pomodoro technique and pair programming. Also Adrienne Lowe’s talk “Coding with knives” and Russell Keith-Magee’s touching talk about burnout debunked the myth of the rock-star programmer, and how important it is to help people to get started on things they’re not comfortable with.

I can’t list all the talks I loved because there are way too many but among those I could find the slides for were Ana Balica’s “Demystifying mixins with Django“, Erik Romijn’s “A sincere tale of Django, developers and security“, Aaron Bassett’s “Effortless real time apps in Django“, James Bennett’s “The net is dark and full of terrors“, and of course Rae Knowler’s “Randomised testing for Django with Hypothesis“.

The 3 days of talks were followed by 2 days of sprints and this was a very good opportunity to dive into Django’s code and start fixing things. The core developers did a good job at helping people setup a development environment and start hacking on the code. This was a very rewarding part of the conference as this allowed me to do my first pull requests on Django and Django CMS.

Thanks to the DjangoCon Europe team who did an amazing job at organizing this event. See you next year in Budapest!

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