Schematic Pin Count Explanation

1:01

Looking for "Mechanical Specifications" in product-1241434-1.datasheet.pdf

Analyzing mechanical features.

Clarifying schematic pins.

Detailing schematic features.

The schematic shows 126 “pins” because the library symbol for your 121-position connector actually breaks out every contact plus every mechanical retention/alignment post as its own Terminal part.

According to the TE datasheet, 1241434-1 is a 121-position, 5-row connector (108 signal + 13 power contacts), but it also includes board-lock and alignment posts that are modeled in the footprint. Those extra five mechanical posts each show up as a separate “Terminal” in the schematic, so:

121 electrical contacts
- 5 board-lock/alignment posts
= 126 total terminals in your schematic

You can safely leave those mechanical posts un-connected (or mark them NC) since they carry no electrical nets.

208 days

tsawye

Which pin numbers should be NC?

208 days

flux

0:53

Identifying component connections.

Determining signal and mechanical pins.

Accessing knowledge base.

Clarifying NC pin requirements.

The five extra terminals that represent mechanical retention/alignment posts—rather than electrical contacts—should be marked NC:

You can safely leave these un-connected or assign them to an “NC” net.

Label NC nets

Exclude NC from DRC

Visually mark NC pins

Remove NC from BOM

208 days

Ready.

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