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Bob Neves is the president of Microtek Laboratories, an independent test facility. Prior to his tenure at Microtek, Bob worked in quality management and engineering in PWB manufacturing. He currently serves as the IPC’s RigidBoard General Committee chairman, Rigid Board Test Method Task Group chairman, Laboratory Qualifications (IPC-QL-653) Committee chairman, member of DESC’s Tiger Team for MIL-P-RRRRR (MIL-PRF-31032), member of BlueRibbon Committee for MIL-S-XXXXX (MIL-PRF-5X) and convenor of IEC TC52 Working Group 10 Printed Wiring Test Methods. You can reach him by e-mail at BobNeves@thetestlab.com or at the company web site: http://www.thetest-lab.com.

Bellcore’s Last Stand(ard)

B Y B O B N E V E S

A N A L Y S I S

From The Lab

You can’t watch ten minutes ofTV without seeing an ad for adifferent telephone company

anymore. I drive through three areacodes to get to work. I long for the daysbefore you had to dial as many as 20+ dig-its to get through to someone. We havecell phones, cordless phones, PBXs,ISDNs, satellite phones, calling cards,network switches, fiber-optics andmicrowave links. Of course, I heard fromthe “older folks” about the days whenyou would pick up the phone, crank adial and ask an operator to connect you.Those days still exist in some foreigncountries I’ve been in, but they seem likeancient history by today’s technologicalstandards.

All these trends in telecommunicationshave created a high demand for newproducts, and with each new productcomes new PWBs (job security). In thepast, if you wanted to build telecommuni-cations products you had to comply withthe Bellcore specification. Well, times arechanging, and so is Bellcore. What weonce knew as the Bellcore institution isgone, and a new private organization hastaken is place. What we have recently seenpublished is what I believe to be the last ofthe Bellcore specifications.

In the printed wiring board industry,we all identify with “The BellcoreStandard” as the communications indus-try specification. Unfortunately, what weknow as the Bellcore specification is real-ly just a small part of a large group ofdocuments. The Bellcore specificationwe identify with is the GR-78-CORE (the specification formerly known as TR-NWT-000078—thank God they gotrid of all those zeroes!). This documentis titled “Generic Requirements for thePhysical Design and Manufacture ofTelecommunications Products and

Equipment.” It is a subset of the FR-78group of documents, which is in turn asubset of the FR-2063 “NetworkEquipment-Building System” family ofrequirements. Our Bellcore specifica-tion, GR-78-CORE, covers the require-ments for PWBs, PWAs, backplanes,cables and connectors. Printed boardmanufacturers need to be concernedwith section six of the document. It con-tains the specific requirements for print-ed wiring boards. Also of interest are sec-tions thirteen and fourteen which definethe qualification and conformance testsrequired for compliance.

Section six of the GR-78-CORE con-tains 248 individual paragraphs. Theseparagraphs are labeled as requirements(R), conditional requirements (CR),objectives (O), conditional objectives(CO), conditions (Cn) and industrypractices (IP). These paragraphs are inmost cases very similar to the IPC-6012with some notable additions. Sections6.1.3.9, 6.2.2.4 and 6.2.2.5 describe therequirements for insulation resistancetesting. This testing, commonly known asSIR testing, comprises much of whatmost people think of as the Bellcorerequirements. For more information onSIR testing, see my column in the June1997 issue of CircuiTree.

Just Who Is/Was Bellcore?Back in the days before deregulation,

there was “Ma Bell” or “the phone com-pany” or just “AT&T”. It was an institu-tion that was as American as the rail-roads, prodigy of the famous phoneinventor Alexander Graham Bell. It was amonopoly to beat all monopolies. MaBell was eventually encouraged to breakitself up. It formed the “Seven BabyBells” or, more formally, the RegionalBell Operating Companies (RBOCs).I’ve never seen any pictures of Ma Bell,but rumors about her and her relation-ships with her children abound.

The septuplets, now weaned and sepa-rated from their parent, banded togeth-er for survival as cooperative siblings andformed a Research and TechnicalCenter. This center was established tomeet their combined appetites for newtechnology and was built around collab-oration and cooperation. This newgroup subsidiary was called BELLCOmmunications REsearch, or BELL-CORE, and was established in 1984 whenAT&T (Ma Bell) broke up.

Just who are the “Seven Baby Bells?”

Ameritech, Bell Atlantic,BellSouth, NYNEX, Pacific Telesis, SBCCommunications,

and U.S. West.

As siblings will, the babies grew up andbegan to enter new markets, all the whiledeveloping more competitive and diver-gent strategies. As the fight for long-dis-tance and cable television businesses

heated up, the Baby Bells faced a futurewhere they would be competing againsteach other for the first time. By the mid-1990s, each baby was doing much of itsown company-specific research whiledeveloping proprietary communicationssoftware. Funding for joint projectsbegan to dry up as each feared leaks ofcompetitive business practices to theother. It was decided by the siblings thattheir group effort, Bellcore, would be putup for sale.

In 1997, Bellcore was sold to SAIC, thelargest employee-owned research andengineering company in the UnitedStates. What does this sale mean? For onething, it means technical support on stan-dardization issues has disappeared. Thelatest version of the GR-78-CORE waspublished during the sale in September1997. In the past, if you had a questionon a specification, you could call the“engineer in charge” and get an answer.That has proved very difficult to do sincethe sale and on-going re-organization. Acase in point is that we found what webelieved were several significant typo-graphical errors in the GR-78-COREeffecting the SIR test and had a difficulttime finding someone to give us ananswer. When we finally found a contact

(Tony Ali), we were told that these wereindeed errors and received a fax fromhim detailing the corrections. It appearsthat there is no intent to revise thisdocument, and I’m sure that very fewpeople have this updated information.The corrections we received are insetbelow:

Corrections to GR-78-CORE:

1. Page 4–9, Note 1: “(1 mm)” shouldread “(1 µm).”

2. Page 6–28, R6–189 second line: “10megohms” should read “104megohms.”

3. Page 13–1, R13–1, Item 3: “13.1.4”should read “13.1.3.”

4. Page 13–1, R13–1, Item 4: “13.1.5”should read “13.1.4.”

5. Page 13–11, Table 13–5, Resistance tosoldering process, for both legend andmarking inks as well as for adhesives:“13.2.5” should read “13.2.3.”

6. Page 14–6, 14.4.1, Item 2, second line:The first “10 ohms” should read “1013ohms,” and the second “10 ohms”should read “1012 ohms.”

7. Page 14–9, Table 14-3, Rows 3 and 4: “3X 104” megohms should read “7 X103” megohms.

It is still unclear whether SAIC willcontinue the standardization effort historically held by Bellcore andwhether the telecommunicationsindustry would even adopt standardiza-tion generated by a privately ownedcompany. The IPC has begun to takeup some of the “standardization slack”left from this change of Bellcore’sfocus. The IPC has a task group whichhas generated detailed information on SIR, and the IPC-6012 PWB per-formance document contains provi-sions for applying some of the uniquetelecommunications industry require-ments to IPC-6012 PWBs. The telecom-munications industry is booming, and Iexpect that standardization in this area will become more complex andfragmented before consensus is generated again. Stay on top of yourcustomers, as their demands upon you may be soon changing. As you allknow, for good or for ill, every babygrows up. Copies of the Bellcore SIR pattern that we generated, alongwith a copy of the fax we received from Bellcore detailing the changes to the GR-78-CORE are available at no charge on our Web site,http://www.TheTestLab.com.

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