InfiniBand Overview for NI 449x DSA Devices


A brief introduction to the InfiniBand bus, specifically regarding the 4X InfiniBand connectors found on NI 4492, NI 4495, NI 4496, NI 4497, NI 4498 and NI 4499 Dynamic Signal Acquisition (DSA) devices.


InfiniBand Standard

InfiniBand is a high-bandwidth I/O communication technology that is typically deployed in data centers, server clusters, and high performance computing applications.  InfiniBand is a high-speed serial data bus (duplexed) designed to directly route data from one point to another point through a switch.  The InfiniBand standard was originally designed for high-bandwidth, scalable I/O bus for connections between computers and disk drives and between servers.  Theoretical transfer rate for one link is 2.5 Gbit/s.  Additionally, links can be aggregated in units of 4 or 12, called 4X or 12X.  Transmission uses LVDS and since it is fully duplexed, four wires are required per connection.  The standard was originally developed by Intel and is now supported by a broad industry group with Compaq, Dell, Hewlett-Packard, IBM, Intel, Microsoft, and Sun Microsystems in the steering committee. 

InfiniBand Connectors

InfiniBand cables use a connector based on the microGiGaCN series developed by Fujitsu.  The connector provides excellent signal integrity with a shield plate between input signal pairs.  Each signal pair is shielded internally, resulting in tight 10% impedance matching, and near-end crosstalk of less than 4% at 50psec rise time.  Additionally, this design minimizes skew, crosstalk and EMI.

InfiniBand on the NI 449x Dynamic Signal Acquisition Devices

With the exception of the NI 4492, NI 449x Dynamic Signal Acquisition (DSA) devices have two 4X InfiniBand connectors, with each carrying eight input channels, AI0-7 and AI8-15. The NI 4492 has a single 4X InfiniBand connector containing eight input channels, AI0-7.


PXI-449x Connector Diagram
Connector AI 0-7
Connector AI 8-15
S1 AI 7 + AI 15 +
S2 AI 7 – AI 15 –
S3 AI 6 + AI 14 +
S4 AI 6 – AI 14 –
S5 AI 5 + AI 13 +
S6 AI 5 – AI 13 –
S7 AI 4 + AI 12 +
S8 AI 4 – AI 12 –
S9 AI 3 + AI 11 +
S10 AI 3 – AI 11 –
S11 AI 2 + AI 10 +
S12 AI 2 – AI 10 –
S13 AI 1 + AI 9 +
S14 AI 1 – AI 9 –
S15 AI 0 + AI 8 +
S16 AI 0 – AI 8 –
GND 1–9 Ground Ground
Shield Ground Ground

InfiniBand Products from NI

NI offers a variety of InfiniBand cabling options including a shielded breakout cable with eight BNC connectors and a 19 inch rack-mountable adapter with 32 BNC connectors.

Direct to BNC Connectivity

A shielded InfiniBand to BNC cable, the NI SHB4X-8BNC  is available in a two pack for direct connectivity to PXI-449x modules. Each cable has a 4X InfiniBand connector on one end and eight BNC jack inputs on the other end.

NI SHB4X-8BNC, 4X InfiniBand to BNC Cable

Rack-Mount BNC

The NI BNC-2144  is a signal connector accessory for PXI-449x modules. It has 32 BNC jack inputs on the front and four 4X InfiniBand connectors on the rear for use with up to two PXI-449x modules. You can mount it on a standard 19 in. rack for simple, direct connections to accelerometers and microphones.

NI BNC-2144, 4X InfiniBand to BNC Rack-Mount Accessory

Shielded InfiniBand to InfiniBand Cable

A shielded InfiniBand to InfiBand cable, the NI SHB4X-B4X is available in 1 m and 2 m lengths for connectivity to the BNC-2144 BNC Rack-Mount Accessory. Each cable has a 4X InfiniBand connector on each end.


Backshell Kit

The 4X InfiniBand connector kit  is designed to be used for custom cabling to NI 449x devices. The kit includes the shell (top and bottom pieces with screws), cable strain relief, PCB for soldering, and connector screws.

4X InfiniBand Backshell Kit

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