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This is a typical PCB from ebay, front and back side:

PCB front and back

The sides are identical, and not mirrored. Which is funny because the A row on the front is the X row on the back.

Is there a logical/practical reason to this, or is it just convenient for the manufacturer to print only one layout instead of mirroring the letters on the other side? I would find it much more useful if the letters were mirrored and could be used to uniquely identify a hole, no matter which side I am looking at the PCB from.

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    \$\begingroup\$ I would say it is not a question to manufacturer, but rather to PCB designer - the person or entity producing Gerber files. I agree with @Trevor you need to ensure that flipping board around the same edge you see A on pad at one side and X on the same pad on another side, it is not clear from your picture (and from your explanation). \$\endgroup\$ – Anonymous Apr 22 '17 at 9:18
  • \$\begingroup\$ The manufacturer hired an inexperienced PCB designer who did not pay attention to this detail. \$\endgroup\$ – coderworks Apr 22 '17 at 16:02
  • \$\begingroup\$ Can you show the whole board btw. \$\endgroup\$ – Trevor_G Apr 22 '17 at 16:04
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You got what you paid for. Rock bottom quality at rock bottom prices. It's typical of cost cutting manufacturing.

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  • \$\begingroup\$ In what way does producing a PCB in this manner "cut costs"? Is it that much cheaper to duplicate the print on the reverse of each unit rather than having a second, pseudo-mirrored print? \$\endgroup\$ – Lightness Races in Orbit Apr 22 '17 at 12:16
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    \$\begingroup\$ @BoundaryImposition I presume it would be, tooling is one of the larger costs of PCB manufacture - one set of silk screen stencils. Probably even only one set of masks for copper, solder mask and silkscreen. Use the same masks for top and bottom sides. \$\endgroup\$ – Tom Carpenter Apr 22 '17 at 12:59
  • \$\begingroup\$ @TomCarpenter: I see! \$\endgroup\$ – Lightness Races in Orbit Apr 22 '17 at 13:05
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There's no logic, practical or convenient reason for this. If what you write is true, it is not a typical PCB. It's a flawed PCB; someone made a mistake.

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    \$\begingroup\$ Or just stereotypical Chinese engineering. \$\endgroup\$ – Ignacio Vazquez-Abrams Apr 22 '17 at 6:13
  • \$\begingroup\$ It is in fact from China. (Updated my question.) \$\endgroup\$ – Simon A. Eugster Apr 22 '17 at 6:38
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    \$\begingroup\$ @SimonA.Eugster It doesn't have to be from China to have a mistake. I once swapped the letters next to a pin header on a board I made. However, I never tried to sell them.. \$\endgroup\$ – pipe Apr 22 '17 at 14:08
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Which side is the "FRONT" ?

Arguably it does not have a front till you put something on it... at which point the labels on the back become meaningless.

Still not too handy though.

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    \$\begingroup\$ Not really. Put item a in hole a1 and a3. Now solder a1 and a3 on the back. Item a falls out. Instructions unclear. Because of the mismatched labels. \$\endgroup\$ – Passerby Apr 22 '17 at 15:43
  • \$\begingroup\$ @Passerby, yes I understand, and agree with you. But figured it was worth a mention. \$\endgroup\$ – Trevor_G Apr 22 '17 at 16:05

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