OBU-301U Information Sheet
V2X On-Board Unit, DSRC stack, V2Xcast®

Overview
OBU-301U is a comprehensive V2X (Vehicle to Everything) on-board unit featuring with automotivegrade hardware and IEEE 1609 WAVE stack. OBU-301U has complete V2X hardware and software to fit the various deployment needs of different OEMs and V2X system integrators. The model enables direct V2X application development to support innovative connected vehicles solutions. Featuring with intuitive V2Xcast® software that provides ready-to-use V2X communication services, OBU-301U supports highest application flexibility for connected vehicles ecosystem development.
Feature
- Feature rich I/O ports provide the most flexible options to integrate with variable devices.
- Painlessly enable V2X on external Linux host device via USB or Ethernet connection and V2Xcast®.
- On-board mPCIe socket allows add-on module.
- Onboard RF compensators provide compensation against RF cable loss. (available in OBU-311 series)
- 5.9GHz and GPS antennas diagnostic detection in case of antenna open or cable pinch.
Specifications
Chipset |
|
---|---|
Operation System | Linux Yocto |
System Service | RS-232 console interface (baud rate 115200 bps) |
System Memory | 128MB NAND, 128MB DDR3 |
Preloaded Firmware | DSRC stack including IEEE 802.11p, IEEE 1609.2/3/4, and SCMS client* (*Est. in Q2 ’21) |
Development Tool | V2Xcast® SDK, including APIs and SAE J2735 facility layer messages |
Hardware Security |
|
DSRC |
|
GNSS |
|
External GNSS Support | NMEA input interface |
External Connector |
|
On-Board Interface |
(*. Support by project) |
LED |
|
Antenna |
|
Operation Voltage | DC 6-48 V ± 5% |
Operation Temperature Range | ambient: -40ºC ~ +85ºC |
Operating Humidity | 10% – 95%, non-condensing |
Storage Humidity | max. 95%, non-condensing |
Housing | aluminum plate, thickness: 1.0mm |
Product Dimension | 103mm (L) x 95mm(W) x 31mm (H) |
Software
Unex OBU-301U enables ease of V2X software development through its V2Xcast® technology. Previously, V2X protocol software had to be built and verified complicated APIs, resulting in a duplicated effort, risk and cost. With Unex intuitive V2Xcast solution that provides ready-to-use V2X communication services for V2X applications, customers can significantly cut time-to-market with less development and testing cost.
V2Xcast is supported in OBU-301U to facilitate V2X application development. It includes two parts – V2Xcast Service and V2Xcast SDK.
V2Xcast SDK
Deploy V2Xcast SDK in either OBU-301U or external application host, it includes APIs to get the services from V2Xcast Service and the main functions of facility layer(J2735), such as message encoder/decoder and example code.
V2Xcast Service
V2Xcast Service image resides in OBU-301U, it combines IEEE 1609 WAVE protocol stack that includes IEEE 1609.2/3/4, SCMS protocol, and POTI. V2X communication protocols will be easily enabled via configuration input without any programming.
Security
Security functions provided by V2Xcast® are designed based on a highly secure HSM (Hardware Security Module).
The highly secure HSM with FIPS 140-2 Level 3 certification is embedded in OBU-301U.
Cryptographic processor eliminates bottlenecks, maximizes application performance and offload CPU’s computation. To protect your sensitive cryptographic keys in a high-assurance key vault, the design provides leverage a keys-in-hardware solution. With the keys-in-hardware solution, all the cryptographic operations are inside HSM and those keys never leave the HSM.
Input Output Interface
Function | Pin |
---|---|
Console (DCE) |
TX(I) RX(O) GND |
Ext GNSS (DTE) |
Ext_GNSS_TX(O) Ext_GNSS_RX(I) Ext_1PPS(I) GND |
CAN0 | CAN0_H CAN0_L |
CAN1 | CAN1_H CAN1_L |
USB | USB_DP USB_DN USB5V GND |
GPIO | GPIO1 GPIO2 |
PWR | POWER RESET GND |
Pin Definition
20 Pin Connector

Pin | Pin Name | Type | Description |
---|---|---|---|
1 | POWER | I | 6-48V System main power |
2 | RESET | I | Reboot the device with rising edge |
3 | TX | I | Serial data from DTE |
4 | RX | O | Serial data to DTE |
5 | GND | G | Ground |
6 | CAN0_H | I/O | CAN0 High |
7 | CAN1_H | I/O | CAN1 High |
8 | USB_DP | I/O | USB Data + |
9 | USB_5V | O | 5V USB bus power |
10 | GPIO1 | I/O | GPIO |
11 | GND | G | Ground |
12 | EXT_1PPS | I | External 1PPS signal |
13 | EXT_GNSS_RX | I | Serial data from external GNSS module |
14 | EXT_GNSS_TX | O | Serial data to external GNSS moduleCAN0 High |
15 | GND | G | Ground |
16 | CAN0_L | I/O | CAN0 Low |
17 | CAN1_L | I/O | CAN1 Low |
18 | USB_DN | I/O | USB Data – |
19 | GND | G | Ground |
20 | GPIO2 | I/O | GPIO |
RJ45
Pin | Pin Name | Type | Description |
---|---|---|---|
1 | TX+ / BI_DA+ | I/O | 10/100Mbps: Transmit data + 1000Mbps: Bi-directional data + |
2 | TX+ / BI_DA- | I/O | 10/100Mbps: Transmit data – 1000Mbps: Bi-directional data – |
3 | RX+ / BI_DB+ | I/O | 10/100Mbps: Receive data + 1000Mbps: Bi-directional data + |
4 | BI_DC+ | I/O | 10/100Mbps: Not connected 1000Mbps: Bi-directional data + |
5 | BI_DC- | I/O | 10/100Mbps: Not connected 1000Mbps: Bi-directional data – |
6 | RX- / BI_DB- | I/O | 10/100Mbps: Receive data – 1000Mbps: Bi-directional data – |
7 | BI_DD+ | I/O | 10/100Mbps: Not connected 1000Mbps: Bi-directional data + |
8 | BI_DD- | I/O | 10/100Mbps: Not connected 1000Mbps: Bi-directional data – |
USB Mini-B

Pin | Pin Name | Type | Description |
---|---|---|---|
1 | VBUS | O | +5V USB bus power |
2 | D- | I/O | Data – |
3 | D+ | I/O | Data + |
4 | BI_DC+ | – | Not connected |
5 | GND | G | Ground |
Typical Using Case
1. Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) applications in standard compliance ITS-G5 stack and messages:
2. Enables V2X on external host device with no impact on existing system architecture:
Simply connect external host device to OBU-301E with preloaded V2Xcast Service, and deploy V2Xcast SDK in the external host device which allows it to send and receive ITS-G5 compliant messages.
Package contents
- One OBU-301E
- Two DSRC omni dipole detachable antennas, 5.9GHz FAKRA type Z
- One GPS active detachable antenna, FAKRA type C, cable length 3 meters
- One power supply unit
- Hardware Guide, software development kit available on Unex server