Data format 'Offspring' sprung.

NORTHBROOK, IL -- A new format for the transfer of electronic data is undergoing final scrutiny and this time it just might gain long-awaited industry acceptance, says the organization behind it.

Offspring, the byproduct of years of debate and code writing, is being routed among IPC member companies. The companies are voting on whether to approve the format--which represents a compromise between IPC and Valor (valor.com), the groups that have for years promoted their own flavors of "intelligent" data transfer.

Offspring actually refers to a pyramid of documents. At the top is IPC-2581, Generic Requirements for Printed Board Assembly Products Manufacturing Description Data and Transfer Methodology, which contains the rules and code. Subdocuments focus on specific data sets such as netlists or land patterns.

According to IPC director of technology transfer Dieter Bergman, Valor made an agreement with IPC to give a reader for ODB++(X). (Valor is not going to change its internal format.) The agreement resolves, for now, the longstanding competition between Valor and IPC over data transfer methodology. In a series of meetings held in Tempe, AZ, earlier this year, representatives from both sides--as well as other interested parties--agreed that an XML schema would be the foundation for Offspring. "The code was what we agreed to," Bergman recalled to PCD&M in a May interview. "It matches the Valor internal structure and matches the domain thinking."

One technical knock on GenCAM was that it was inherently flawed because it was based on padstacks, and users lose the association when designs are broken down to layer to layer. On the other side, ODB++ users have called the Valor tool difficult to implement. While denying that GenCAM was technically lacking, any confusion stemming from past formats have been resolved, Bergman explains. "GenCAM is hierarchal, you see the board in all its entirety. Offspring is layered; a given set of features is all on an individual layer, so fabricators can make changes to a layer without changing [anything else]."

IPC-2581, says Bergman, "takes the [ODB++] structure and grinds and polishes it."

Association members in June began the final review of IPC-2581. Based on history, it will take multiple reviews--"ballots," in IPC parlance--to finalize the standard. What remains is to incorporate any final changes and prove the format through the building of golden boards, Bergman says. Yet as someone who has spent three decades trying to improve the industry's data transfer protocol, he knows that implementation ultimately depends on acceptance by the tool makers. And some, he says, are crying poor, alleging a lack of resources. To that end, specialists at the National Institute of Standards and Technology (NIST) are writing an applications program interface (API) and have modeled a generic PCB, Bergman says, with the goal of aiding implementation of IPC-2581 into CAD software.