my customer wants to know what are the advantage of using the 1310 as AP vs using 1242 AP for outdoor users. We know that we can wired the 1242 internally within the building and extend the antennas to outdoor for outdoor users. I know that the 1310 is for outdoor but is there anything else that can help us get the client to buy the 1310 instead of using 1242. We do not do bridging.
The 1310 supports 802.11b/g only and 1242 have dual radios and by this support 802.11a/b/g. So this depends on the needs on your clients. If you dont need long antenna cable runs the 1242 could be enough and is also cheaper. Or put it in a NEMA enclosure and use PoE to feed it.
The shorter your antenna wires are, the less signal loss you are going to get. How far will the AP be from the antenna? If it's 10 feet, I wouldn't worry about it -- but if it's 100 feet it could be a major problem, depending on how much signal strength you need.
Also, the RG6 coax required for the 1310 between the "power injector" and the access point is MUCH cheaper than the antenna wire you'd have to run for the 1242. It's much thinner, easier to run in small spaces, more flexible, and much easier to terminate.