OBU-301U Information Sheet

V2X On-Board Unit, DSRC stack, V2Xcast®

OBU-301U:V2X On-Board Unit, DSRC stack, V2Xcast


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 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.


  • Autotalks® CRATON2 V2X communication processor
    • dual 600MHz ARM Cortex-A7 32-bit CPU cores
    • 1140 DMIPS processing power each Cortex-A7 core
    • ARM Cortex M3 32-bit processor with memory protection unit (MPU) and ECC protected memory
  • Autotalks® PLUTON2 V2X RF Transceiver
  • Embedded Hardware Secure Module (eHSM)
    • Dedicated ARM Cortex-M0 CPU
  • Telit® SL869-V3 GNSS module (SL869-ADR optional)
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
  • Dedicated ROM containing certified secure V2X signing firmware
  • Secure encrypted off-chip storage of private keys
  • Private material is inaccessible outside HSM
  • Capable of >110 signatures / second, with <9ms signing latency for ECDSA NIST P256 or ECDSA Brainpool P256R1
  • Line-rate ECDSA verification engine (>2500 ECDSA NIST P256 verifications / second)
  • Embedded HSM supports less than 9ms latency on ECDSA NIST P256 signing, it’s granted FIPS 140-2 Level 3 certification*
  • Tamper detection
  • Frequency band: 5.85 ~ 5.925 GHz
  • Radio mode: 802.11p
  • Channel: 172, 174, 176 , 178, 180, 182, 184
  • Channel bandwidth: 10MHz (5MHz & 20MHz by project)
  • Data rate: 3, 4.5, 6, 9, 12, 18, 24, 27Mbps for 10MHz BW signal
  • RF transmit power: > +20dBm, Class C RF spectrum mask compliant with margins
  • RF receive power: < -92dBm, compliant with SAE J2945
  • Refresh rate: 10Hz
  • Sensitivity:
    • Acquisition: -146dBm
    • Navigation: -158dBm
    • Tracking: -162dBm
  • NMEA Standard: NMEA 0183
  • Accuracy: 1.5m (CEP50 with SBAS)
  • Telit® SL869-V3 GNSS receiver supports GPS/Glonass constellations. SBAS like EGNOS (EU), WAAS (US), and MSAS (JP) are also supported
External GNSS Support NMEA input interface
External Connector
  • One integrated 20-pin I/O interface
    • Power 6-48V DC
    • Reset
    • One RS-232 for Console (baud rate 115200 bps)
    • One RS-232 for external GNSS NMEA input
    • One 1PPS input
    • Two CAN
    • One USB with USB bus power
    • Two GPIOs
  • One Ethernet port with 802.3af PoE
  • One USB Mini-B port
  • Two FAKRA Z RF port for DSRC
  • One FAKRA C RF port for GNSS
On-Board Interface
  • Two MMCX RF connector (DSRC with remote compensator power & control signal)
  • Two MHF RF connector (DSRC)
  • One MMCX RF connector (GNSS)
  • One Mini PCIe slot (for LTE module) *
  • One SIM slot*
  • One PoE Module slot
  • One Reset button
  • LED headers
  • Boot strapping DIP switch
  • JTAG 7-pin header

(*. Support by project)

    • Start-up: Blinking Green
    • Operational: Solid Green
    • FW upgrade: Amber (R+G)
    • Fault: Red
  • PWR
  • 1PPS
  • LED0
  • LED1
  • Two detachable FAKRA type Z DSRC 5dBi Omni Dipole
  • One detachable FAKRA type C active GNSS antenna, cable length: 3 meters
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)


1. Hostless Mode: OBU works as a standalone full-featured V2X unit
OBU-301U System On Module,Applicaon Host
2. Hosted Mode: OBU works as a V2X communication unit to existing application host
OBU-301U System On Module,Applicaon Host

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.


OBU-301E System On Module,V2X safety msg, app

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

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
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


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

  1. One OBU-301E
  2. Two DSRC omni dipole detachable antennas, 5.9GHz FAKRA type Z
  3. One GPS active detachable antenna, FAKRA type C, cable length 3 meters
  4. One power supply unit
  5. Hardware Guide, software development kit available on Unex server

    Contact Unex

    Discover unlimited V2X opportunities & start the journey with V2Xcast®

    Global Headquarters

    7F-2, No.100, Sec.1, Jiafeng 11th Road., Zhubei City, Hsinchu County 302052, Taiwan



    mPCIe System-On-ModuleOn-Board UnitRoadside UnitStarter KitOthers

    DSRC stack, U.S.ITS-G5 stack, Euro.C-V2X stack, U.S.Others


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