A supplier's CAT ECM photograph may illustrate a product family rather than the unit being offered. Before placing it beside the removed controller, ask what the picture represents. An accurate visual comparison starts with two identified items, not two images that happen to look similar.
Establish which item each photograph belongs to
Keep the removed unit's images together under one identifier. Do the same for the supplier's set, linking it to the quotation and offered reference. A label close-up taken from one item and a connector view taken from another cannot establish a complete match.
Ask whether the supplied pictures show current stock, a representative example or the particular unit reserved for the order. These answers have different meanings. A representative image can help explain a shape, but it cannot document the condition or markings of the item that will be shipped.
If the seller cannot yet identify a particular unit, record that limitation. Do not describe the photograph internally as a pre-shipment inspection. Keep a later image set separate so colleagues can tell when the evidence changed from an example to an identified item.
Make equivalent views before looking for differences
Compare the same side of each housing. Use the label position, mounting features and connector edge to establish orientation. Rotate a copy if necessary, but retain the original and do not mirror the image to make its features align.
Scale on a screen is not a reliable measurement. Cropping and camera distance can make different-sized units look equal. Where size is relevant, use a documented dimension or a clearly described measurement instead of judging the width of two photographs.
Request another view only to answer a specific open question. A second front photograph will not clarify a hidden connector lock. Name the feature that needs to be shown, so the supplier can provide useful evidence rather than a larger collection of similar pictures.
Mark differences without deciding what caused them
A different cover finish, missing bracket or unreadable label is an observation. Its cause may not be visible. Keep the comparison factual rather than declaring a unit unsuitable, modified or genuine from a surface detail alone.
A visible connector or mounting discrepancy does need an explanation before approval. The guides to connector orientation and mounting-hole comparisons address those narrower checks. Neither turns a visual resemblance into application confirmation.
A handwritten note in an image may help associate the picture with the enquiry, but it does not independently prove provenance, function or authenticity. Keep the seller's written description and reference alongside the images instead of asking one photograph to prove everything.
Appearance does not describe the loaded configuration
A housing photograph cannot establish the software or configuration within a controller. Ask separately what the offer includes and which application is supported. A clean case is not a functional test, and a familiar label is not evidence of every later change.
Likewise, any reported test needs a defined scope. Preserve what the supplier actually says was checked. Do not turn a statement about communication or power-up into a claim that the module has been verified for all functions on the intended machine.
Preserve the original image files when possible. Repeated forwarding or screenshots can make small markings unreadable. If an enlarged copy is supplied, keep it labelled as an enlargement rather than treating sharper-looking characters as new evidence.
Connect the accepted comparison to shipment
Before dispatch, confirm that the supplied reference still agrees with the approved quotation. If the offered unit or reference changes, obtain the relevant evidence again. An earlier comparison cannot silently approve a different item simply because the order quantity is unchanged.
Use the CAT parts category to locate an identified requirement. Save the accepted image set and unresolved limits with the order. At receipt, the team should be able to compare what arrived with what was actually offered, without mistaking a catalogue illustration for a record of the delivered unit.
