SUMIT™ Resource Label

A table has been designed which conveys interoperability of a company’s SUMIT-compatible product since all the interface signals may not always be supplied by a SBC or used by an I/O module. Its purpose it to quickly show sources and uses of resources on the SUMIT connector and how a designer engineer/vendor has implemented SUMIT’s various interfaces on their product. It standardizes sizing/aspect ratio so it's easy to find at a glance on any labeling for SUMIT-enabled products. It should be included in both marketing data sheets and technical manuals for reference by a system designer using SUMIT products.

The label lists resources available for both the SUMIT A and B connectors. If the SUMIT signals are not defined for the connector, then the box area is grey. If a signal or interface is not supported, a dash should be in the box rather than leaving it blank. If one of the A or B connectors is not supported or populated, all the boxes should be grey indicating that no resources are available.

Form factor means the size of the board using the SUMIT interface. For example, a board may be an ISM (Industry Standard Module), Pico-I/O, Pico-ITXe or other custom-size board.

For PCIe and USB only the number of channels supported/used should be listed in the box corresponding to which connector the signal is used. For ExpressCard and LPC only a check mark or dash should be used indicating presence or absence of these interfaces.

SPI and uWire are combined together on the label. Either SPI or uWire should be put in the box to indicate which protocol is supported on an I/O module. Use the word “Both” if a SBC could support both.

SMBus and I2C are combined together on the label. Either “SMB” or “I2C” should be put in the box to indicate which protocol is supported on an I/O module. Use the word “Both” if a SBC could support both.

For power, a check or dash needs to be included in each box indicating whether the card needs or provides that resource. If an I/O card can use or generate different voltages, then use the term “Opt.” to indicate multiple options are available and the designer should refer to its datasheet. The current available by the SBC or required by the I/O card is not listed. These system configuration and power distribution issues are beyond the scope and intention of the label.

If additional information or explanation is needed about the card, there is a small amount of room at the bottom of the label for explanation or reference. The last line lists a URL of the SFF-SIG that will keep up-to-date information.

Example Labels

Three examples are shown to the right. The first is an ISM (90mm x 96mm) SBC with two PCIe x1 links, no PCIe x4 links, 3 USB 2.0 channels, ExpressCard, LPC, SPI/uWire, SMBus/I2C, and various power sources. It does not list the processor used, but that would be permissible to note it at the bottom of the label if desired.

Also notice that the power sources may be either pass through from the power supply or generated from onboard power supplies. The manufacturer needs to list the current supplied in their published technical literature and provide sufficient technical data to allow a designer to properly understand sources and uses of the power and individual interface signals on their SUMIT product.

The second example shown is a label for a Gigabit Ethernet SUMIT-ISM card with a PCIe x1 interface. This card has a number of different power options depending upon whether Wake on LAN is implemented.

As shipped, it uses +5Vsb to support the Wake function; however, there are jumpers on board to allow optional use of either +5V or +3.3V. Note that this information should be in the manual and the label indicates optional power configurations are possible.

The third example to the right is a Pico-I/O board populated with only a single SUMIT A connector using an LPC interface. Since this is a simple I/O board, no SUMIT B connector is used. Also, it is a +3.3V only board.


SUMIT interfaces equally to high-, moderate-, and low-speed designs and is form-factor independent; giving engineers’ extreme flexibility and scalability with their design. As a result, the SFF-SIG created a resource label which lists the various interface resources and interoperability of a vendor’s SUMIT-compatible product.

This label is not all-inclusive but is designed to quickly convey meaningful data in a simple, universal format. There are many other variations that can be documented using the SUMIT label which will generate the possibility of confusion, misunderstanding, and/or incompatibility since not all signals are required to be present on a SUMIT connector. If you have questions or comments about how to implement a SUMIT label for your product, please contact the SFF-SIG office.

Last updated June 12, 2011
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