No it's not. If you read the thread (including the last post) you'd see that there's a setting on CDMA networks that tells the phone how often it should check in with the tower to see if there's an incoming call. They call that the "slot index". The total time interval in seconds is 1.3 * SI + 1.3. You can look at your slot index by opening the dialier and entering ##DATA# (##3282#). When you hit the last pound sign (#) the phone will take over and ask you if you want to view settings or edit them. You need a code from Sprint to edit them but you can look at them on your own. My slot index was 2, so my phone is only checking in every 3.9 (1.3 * 2 + 1.3) seconds.
I was with TMobile for 5 years before I switched to Sprint, and there were times when I would call my dad (who's been on Sprint for a long time) and his phone would only ring once or twice even though I had heard 5 or 6 rings on my end. I don't remember exactly what phone he has; I think it's a Palm Centro.
Now, there also appears to be the issue of Android 1.5 not supporting CDMA natively, and that also appears to have something to do with it. But it is at least partially a Sprint issue.
Ok guys, so thanks to big_z, i was able to research this a bit more. Found some good info out there, all of it essentially saying the same exact thing as to how this process works.
There is a link to the Sprint forums that someone posted, and I forget who, but they get the credit:
Suggestions for Sprint:Time the phone rings before voicemail...
This thread actually breaks it down a little more as well.
I just got off the phone with Sprint Advanced Technical Support. First off, and I'm not going to go in a long rave about this, but I don't want to hear anyone say that they have bad CS. Every call I've made to them has been pleasant and helpful. In this particular case, I actually gave the Technician a lesson (as he was unaware of the slot cycle index info, etc), but he was extremely willing to work with me and experiment to figure this out. He gave me my MSL and we went to work!
Here is what 1 hour on the phone determined. Please take all of this with a grain of salt. My phone is 1 out of thousands out there, and the testing has been limited, so that being said....
After accessing the programming screen using my MSL, we went into the Advanced tab. Sure enough, there was the slot cycle set to '2'. I hit the setting and it brought up a menu to change it between 0-7. At first, for laughs, we set it to 7.....I should preface this by stating that he called my phone to set the benchmark before making any changes, using all kinds of ringtones (custom, short, stock, etc) and i would pick up the phone the first sign of vibration/audio notification. Each time I picked up, his end was on ring 4. After 5 rings, it goes to VM (this is set by Sprint and is not changeable). This kind of proved that it wasn't the ringtone causing the issue.
Anyway, we set it to 7. Based on what I've read (in that Sprint Forum), the equation for the slot cycle is 1.3xSI + 1.3 = time (seconds) that the phone checks the towers for calls. 7SI should have bumped this to 10.4 seconds. I set the SI to 7, saved the changes, the phone rebooted and we tested. Same result. 4 rings on his end when i picked up at the first sign of audio notification.
We then went back and set the SI to 0. We tried this with both a stock ringtone and my custom ringtone. the result was me picking up after his end rang 2 times. NICE!! We gained 2 rings!! I've tested this about 5 times myself, calling my self with my house phone, and the results are consistent. It rings 2 times on my end before the audio/vibration on the Hero. Not too bad. I found another tip on the Sprint Forums *credit to whoever posted it* that if you go to Settings>Sounds and Display>Roaming Alert and uncheck that, the phone won't "check" to see if it's Roaming before each call comes in, thus gaining another half to full ring. With all of this done, I can now say that calling my phone using my house phone, while my cell phone is "sleeping", i will get audio/vibration notification in 1.5-2 rings.
The downside to this is battery life. With the phone checking the towers that much more frequently, there is bound to be a bit of a hit on the battery. How much is yet to be determined. I plan on leaving my SI at 0, at least over the weekend to see what happens. I will get a better feel over the weekend than at work because my signal at work is sketchy, and I've got anywhere from 4 hours (going down to 20% battery) to 8 hours (going down to 80%) battery. At home it's consistent in battery usage. I've read more than one person say that changing the SI to 0 has had a minimal to unnoticeable effect on battery life.
My suggestion to everyone affected by this, would be to politely call Sprint Advanced Technical Support (1.877.345.7895), explain to them the situation (the more technical detail you can give, the more they help...at least in my experience), explain what you'd like to do (via the ##3283# menu, using your MSL). If they don't know what you're talking about (as mine didn't, I basically read the info that I've gathered from the boards) explain it to them. Have them work with you by getting your MSL and follow the steps.
Again, testing has been limited thus far, but the results have all been positive. The guy that was helping me advised that this would probably wear the battery down a bit, and I just told him that a full battery does me no good if I can't answer the phone. He agreed.
Good luck everyone! Report back with results if you can.