Telecom hardware is unusual in that the electrical performance is agreed before the artwork exists. A link budget, a loss target and a return-loss figure are negotiated with the customer, and the board only works if every batch reproduces the stack-up those numbers were calculated from. That makes the stack-up the specification, and the fabrication record the proof.
Why impedance is the specification
A controlled-impedance board is not a trace width chosen once. The dielectric, the copper thickness and the layer spacing fix the impedance together, so changing a laminate to save cost or time changes the electrical result. The stack-up is therefore agreed with engineering, frozen on the quotation, and verified on impedance coupons taken from the production panel. The published tolerance and the rest of the process limits are on the capability page.
Choosing the laminate
Where a section runs at a frequency or a loss budget that FR-4 cannot meet, a high-frequency material is used for that section while the digital layers stay on ordinary laminate. Mixed constructions let one board carry both without paying the RF price on every layer. The decision follows the frequency and loss budget of the design; the material list is on the high-frequency PCB page.
Where a telecom programme stops being a stack-up
A link budget is divided before any board is drawn, and the board only carries one share of it. Connectors, cables, the antenna and the front-end parts take the rest, so the same impedance target can be comfortable on one design and impossible on another. An enquiry that arrives with a stack-up and an impedance figure but no split of the loss budget leaves the board side guessing at which share it is being asked to hold: the stack-up is then drawn to look controlled, and the shortfall shows up later in a system test rather than on the drawing.
The board is measured in two different places, and it helps to keep them apart. A coupon taken from the production panel says what the laminate and the geometry actually did, which is the only thing the fabrication side can prove; return loss across a populated link is decided by connectors, cable assemblies and the assembly work as much as by the traces. A programme that measures only at the coupon, or only at the system, spends its debugging time on the wrong half of the link.
Change control is the third boundary. A revision that alters the laminate, the board thickness or a connector footprint moves the electrical result for every variant that follows it, while boards already released keep running on the older construction. Settle the split of the link budget and the interface definition before the stack-up is frozen, and the board has to be built correctly only once.
Multi-variant builds without a separate line
Networking products arrive as families: one stack-up, several populations, sometimes a variant that differs by a single connector. Each variant is quoted from its own data package, so a small board does not carry the price of the largest one, and a prototype of one to fifty pieces runs on the production lines before the family is released.
Records, confidentiality and visits
Fabrication and assembly share one plant, so an impedance reading, a first-article result and a final test record belong to the same lot record. The inspection sequence is described on quality assurance, and the certificate set — ISO 9001:2015 and UL file E354070 alongside RoHS — is scanned on the certifications page.
Drawings and link budgets can travel under a mutual NDA from the first exchange, and a visit to the Shenzhen or Meizhou plant can be arranged around the processes the board would use. Payment is by bank transfer (T/T), with goods quoted EXW Shenzhen or DDP.
What a telecom quotation is actually pricing
Two quotations for the same Gerber set rarely differ by board area. They differ by how much of the link budget has been turned into a measurable step, and that work is priced alongside the fabrication.
- Making the impedance and the loss measurable. Coupon design, coupon sampling from the production panel and the impedance or micro-section data that travels with the lot turn the stack-up into evidence, so the board side can show that the path it was asked for is the path it built. System-level return loss stays with the customer or the test house, and the two records together say which part of the link was verified where.
- Building a family as one construction. Variants that share a stack-up can be pressed and sampled together, so the differences between them stay in the population and in the test coverage rather than in the laminate, and a small variant does not need its own coupon round. The sequence behind that coverage is described under PCBA testing and quality assurance.
- Re-confirmation after a change. A new laminate, a different board thickness or a revised connector footprint moves the impedance and the loss, so a revision returns to the confirmed state and is re-run and re-recorded instead of being released as a drawing update and found out at a system test.
Price and evidence move together here as well. An order that carries less of the second is not cheaper in total; it moves the system-level confirmation back into the customer's programme, where it is paid for again after a certification test or a first failure. A quotation that states which checks and which records are included lets the difference be read as a difference in proof rather than as a markup.
Next step
Send the Gerber set, the stack-up and impedance targets, the BOM if assembly is included, the quantity and the target date. Board families used in telecom work have their own pages — high-frequency, HDI and multilayer — and turnkey assembly covers the build after the board. Security products that share an enclosure with radio front ends are described under security system PCBs, the rest of the industries we serve are on the industries page, and a quote can be requested on the contact page.
