When the Sierra AirCard 595 first shipped, it was the first EVDO Rev A PCMCIA card that Sprint shipped in September 2006 and it was the first EVDO Rev A Card that Verizon shipped in December 2006. A few days after the 595 shipped from Sprint, we started a thread on EVDOforums: AirCard 595 Antenna Connector. The AirCard 595 had an antenna connector (to hook up antennas and amplifiers), BUT it was proprietery. No existing cable would work, so there wasn't a way to hook up an external antenna.
Sierra Wireless was selling a cable for $39 + $25 shipping, just for the cable (that didn't include the antenna), but it was also the wrong connector (it was SMA vs. FME).
A few months later and we now have AirCard 595 cable adapters custom built and we are able to offer the same antennas and amplifiers that we do for all other mobile broadband cards (except PC5740 which doesn't have an antenna port):