Why would he need an Advanced System Key? With the right flash, an APX can use the older style software system keys.
What he said....people are confusing a "hardware" key (ASK/ACK) with a software System Key. A software System Key can be used for a Smartzone/Omnilink system with an Astro or Astro25 or APX radio. Your APX needs the proper flashcode option to allow legacy software System Key to be used. Both 3600 (mixed mode) and 9600 (P25 only) systems can be programmed with a software System Key (the APX flash option for soft key is option QA01749AB...on a new radio, this is a no charge option).
A software system key will allow you to create/edit trunking systems/personalities in the CPS. A system key can be generated with skeygen.exe and the system ID or using a hex editor. Once the key is uploaded, you can then use the CPS to program it to use a conventional frequency to call a trunked scanlist that has your talkgroup(s). Radio will not affiliate and it cannot be seen.
With regard to legacy software system keys created for SZ/SN or P25 Tunking systems for Motorola Astro and Astro25 (and appropriately optioned APX) subscriber radios, there is no difference in the format of the data contained within the system key.
To enable read/write restrictions you will need an Advanced System Key (ASK) or an Advanced Conventional Key (ACK) which resides within a dongle which needs to be physically connected to the PC/Laptop while reading/writing/programming. As long the radio you purchased is not ASK locked, you don't have to worry about that.
Or you could just buy and Phase II capable scanner (PSR-800, uniden 436/536) for thousands cheaper...
Or you could monitor the Newark Fire feed hosted on broadcastify....