We often picture a charging station as a very large "power socket".
In reality, it is an intelligent, interconnected object that communicates with multiple systems. But with what, exactly?
Here is an overview of the different ways a charging station communicates.
The different languages a charging station speaks
1- The station communicates with the vehicle
To operate, a station must first talk to the vehicle. This communication is governed by international standards.
a. IEC 61851: the "basic conversation" between station and vehicle
This standard defines the exchanges required to start and secure a charging session. It enables:
- detection and identification of the vehicle,
- definition of the charging mode (mode 3 for AC, mode 4 for DC),
- authorisation to start charging,
- negotiation of the acceptable current level,
- dynamic power modulation via a PWM signal (Pulse Width Modulation),
- fault detection (earth fault, poor connection, etc.).
Without this standard, the station cannot manage charging intelligently.
b. ISO 15118: the "advanced conversation"
This standard goes further: it lets the station and the vehicle exchange detailed information over PLC (power line communication). The data transmitted includes:
- the state of charge (SoC),
- the vehicle's physical identifier (VDI),
- cryptographic certificates.
It opens the door to:
- autocharge (automatic vehicle identification),
- Plug & Charge (no badge, automatic authentication),
- and even V2G (vehicle-to-grid).
2. The station also communicates with the DSO
The DSO (Distribution System Operator) is the operator that manages the electricity network (such as Enedis in France).
In private settings, communication with the DSO is essential for fine-grained power management. The station can talk to the meter through a dedicated contact (e.g. SECC) or through the TIC (Télé-Information Client) interface of Linky meters. The goal is to know how much power is actually available, to avoid tripping the breaker and to adapt the charge dynamically — but also to take advantage of attractive electricity tariffs (off-peak hours). In France, these are often referred to as "Linky-ready" stations.
For more advanced logic (demand response, load shifting, smart grids), some stations are managed by CPOs interfaced over OSCP (Open Smart Charging Protocol), supported by the Open Charge Alliance, with various energy systems: battery managers, flexibility players, or DSOs depending on local energy-market specifics. In every case, OSCP makes it possible to optimise charging against grid constraints, leaving the CPO to translate the setpoint into smart-charging commands sent to the station.
3 - The station communicates with the CSMS, the CPO's brain
The CSMS (Charging Station Management System) is the central system a CPO uses to communicate with its stations. Stations connect to it:
- either directly over the internet (3G/4G/5G SIM, secure VPN),
- or through a local concentrator over a wired link (Ethernet) or wireless (Bluetooth, Zigbee).
a. The language used: OCPP
Exchanges take place over OCPP (Open Charge Point Protocol), in its various versions (1.5, 1.6 JSON, 2.0.1). OCPP notably enables:
- session authorisation,
- power management,
- command dispatch (locking, stopping, restarting, etc.),
- remote supervision (logs, updates, diagnostics).
b. Data sharing: OCPI
To publish static and dynamic station data (availability, tariffs, CDRs), the CSMS uses OCPI (Open Charge Point Interface) (2.1.1, 2.2). This protocol allows exchanges:
- either directly (peer-to-peer) between players,
- or through roaming / interoperability platforms such as GIREVE or Hubject.
4- Other forms of communication exist
Some stations exchange data with local energy systems (photovoltaic panels, batteries, EMS — Energy Management Systems). They then use industrial protocols such as Modbus or CAN.
Not every station speaks OCPP natively, either. Some use a proprietary internal protocol, a third-party protocol, or a translator to OCPP. This is common in master–satellite architectures, where a "master" station drives several "satellite" stations.
5- To conclude…
The CPO business rests on a fine-grained understanding of this complex technical ecosystem: standards, protocols, compatibilities and varied architectures.
Technical monitoring and engineering, along with the technical qualification of equipment, are therefore crucial to guaranteeing optimal service quality for charging users.
At Yusco, together with our partner Le Plein, this complexity is our daily work.
Understanding these protocols, their limits and how they evolve — and working closely with equipment suppliers — is essential to guaranteeing a reliable, durable and secure network at the service of Le Plein network users.