Hirose makes a lot of small signal connectors, including U.FL micro coaxial connectors. They’re even kind enough to put these connectors together into cables that can be quite useful for RF antenna applications.
Sometimes though, you’ll find a pair of Hirose part numbers that appear outwardly identical, such as U.FL-2LP-088K1T-AC-(50) and U.FL-2LP-088K1T-A-(50). Hirose’s documentation doesn’t explain the difference between these two parts, nor does one show up in Digi-Key’s parametric filter information. So what gives?
The answer is connector orientation. On the ‘A’-marked cable, both of the U.FL connectors are oriented the same way - if you lay the cable out flat on a table, both connectors would be pointed ‘Up’, in the same direction. On the ‘AC’-marked cable, however, one of the two connectors is reversed. If you lay the cable out flat on a table, one connector would be pointed ‘Up’, while the other would be pointed ‘Down’.
This can help with cable routing and minimizing unnecessary bends or twists in your RF cable, which can become sources of difficult-to-troubleshoot signal distortion. Make sure to select the connector orientation that best fits the cable routing you’re expecting to use in your system.