A high-layer-count backplane held at a raking angle in a black inspection fixture, its dense fine traces and rows of press-fit pins reading as an even texture

Industry · telecom & networking · Group C manufacturing sites · Shenzhen

Telecom, networking & 5G

A networking programme is decided before the first board: by impedance control, by consistency at a second site, and by the EMC class the box may enter.

Send us your stackup The five Group C sites

Layer envelope

1–58

Layers published by one Group C fabrication site, with 0.1 mm trace and space

Placement

80k CPH

Single-line placement rate published at one Group C assembly site

Coverage

12/24

Sites listing ISO 9001 — 15 list RoHS, 15 list CE, two list none

EMC split

A / B

FCC Part 15 Class A excludes the residential market; Class B is the residential class

01Pain points · what decides the programme

Four numbers that decide the build.

1–58 layers12 / 24 ISO 9001FCC Part 15 A / B

Each figure carries the source it came from.

An engineer's test bench in a dim clean room: a rack-mount oscilloscope with an unlit screen, a bench power supply with blank readouts and a finished board assembly under a magnifier arm

P-01

Impedance decides the stackup

Rogers, PTFE and mixed-dielectric builds only work inside a fabrication envelope that can hold controlled impedance.

0.1 mm trace1–58 layers0.15 mm drill

Source · network fabrication envelope

A finished board assembly in a machined aluminium housing beside a bare multilayer production panel resting in a white inspection fixture

P-02

The second site is where consistency dies

The same BOM produced at two sites diverges on impedance, warp and cosmetics, so the site is the unit of qualification.

12 / 24 ISO 900115 / 24 RoHS2 list none

Measured · 13 September 2026

Four finished rack-mount network switches standing in a row, closed faceplates with empty port cages

P-03

EMC class decides the market

FCC Part 15 Class A is for commercial and industrial sale and excludes residential; Class B is the residential class.

Class B 66–56 dBµVClass A 79/663 m vs 10 m

Source · 47 CFR Part 15

A single technical drawing sheet seen from above with a pen, dividers and one tab marking a clause

P-04

Certification dates are not interchangeable

62368-1 has four distinct events, and the 4th edition drops acceptance of components approved to 60950 or 60065.

2020-12-202025-07-10DOW 2027-02-15

Source · UL · CENELEC

02Technical requirements · written into the spec

What a hardware engineer releases a stackup against.

IPC-A-610JJ-STD-001JIPC-6012F

Fabrication, assembly and acceptance, from the sites' published envelopes
Parameter	Published value	Basis
Fabrication	1–58 layers; 0.1 mm trace and space; 0.2–3.2 mm thickness; 0.15 mm drill	Group C envelopes
Copper and holes	Outer copper 1–8 oz, inner 1–4 oz; PTH ±0.08 mm; annular ring 0.15 mm	Published tolerances
Assembly	0201/01005 minimum; 75,000–80,000 CPH; 3D SPI, 3D AOI and X-ray	Two Group C sites
Acceptance documents	IPC-A-600M, IPC-6012F, J-STD-001J, IPC-A-610J	Current revisions

A close view down one SMT line, pick-and-place heads and feeder reels in strict alignment — Fig. 01Process data is the evidence. Placement, SPI and AOI records are what a repeat build is judged on.

A flat technical diagram of a route line with four stage markers and two teal transfer bars — Fig. 02Every stage carries a limit. Fabrication, assembly, test and shipment are separate acceptance events.

A cross-sectioned plated through-hole seen through a microscope objective, the copper barrel wall and the laminate layers in clinical laboratory light — Fig. 03Acceptance has a document behind it. Where Class 3 applies, a sectioned coupon is what a claim is checked against.

Related How quality is controlled PCB fabrication & PCBA

03Connection layer · what we supply

Five independently operated sites behind one contract.

Group C · 4 sitesGroup E · 1 site

Every figure on these cards is a site's own published product or capability number.

A finished populated circuit board assembly for a power supply laid flat, photographed from directly above with a processor, heatsinks and terminal blocks in view

C-01

Saturn PCBA — 1–58 layer fabrication

Multilayer, HDI, flex and rigid-flex with assembly and turnkey box build, from a Shenzhen plant working since 1998.

1–58 layers9 SMT + 4–5 DIPNo MOQ

Group C · lists ISO 9001 and UL 796

Pick-and-place heads and feeder reels aligned along a single SMT line, seen close down the line

C-02

Whale PCBA — 2–32 layers, 8 SMT lines

Prototype to mass production with 3D SPI, 3D AOI and X-ray at every stage, and a free DFM review inside 24 hours.

8M placements/day98.7% on-time30+ countries

Group C · lists ISO 9001, IATF 16949, ISO 13485

A finished populated circuit board assembly standing upright on edge, a matte black heatsink across its upper half and a row of connectors below

C-03

Uppcba — prototype to mid-volume

One prototype or ten thousand units on the same line, with a minimum component size of 0201/01005.

No MOQ75,000 CPH99.7% first-pass

Group C · lists ISO 9001 and ISO 13485

A finished board assembly in a machined housing beside a bare multilayer production panel held in a white inspection fixture

C-04

Kingdta — sensor and radar modules

Vibration, angle and microwave radar modules, built with their own PCB, FPC and PCBA lines under MES traceability plus functional test.

6 SMT + 6 DIP±0.03 mmChinese-language site

Group C · lists ISO 9001 and RoHS

Two finished industrial computers side by side on a pale bench, one a slim fanless Mini-ITX enclosure with heatsink fins, the other a rack-mount unit

E-01

GEOLiNK — industrial motherboards

28 models across six form factors from 2.5-inch to Mini-ITX and NUC, qualified from −20 to +60 °C on 9–36 V DC.

6 form factors−20/+60 °C28 models

Group E · lists CE, FCC and CCC

04Trust layer · standards that apply

Codes only, stated for what each one covers.

No holder namesNo certificate numbersNo bare CE claim

01 UL 796 is the bare-board standard UL's own vocabulary is Listed and Recognized Component, not a mark of its own; the catalogue lists the edition as Active without a year.

02 FCC Part 15 has two compliance routes §15.101 lets most unintentional radiators use SDoC or Certification. Scanners, radar detectors and Access BPL must be Certified.

03 CE is a declaration, not a certificate The manufacturer signs an EU Declaration of Conformity, covering EMC 2014/30/EU, the Low Voltage Directive and RoHS as applicable.

04 REACH has no mark at all Its obligation is information under Article 33 above 0.1% w/w. RoHS restricts ten substances, cadmium at 0.01%.