I have not been much around that RC/servo stuff etc. But from what I read through multiple blogs/articles/forums/etc you are suppose to vary your PWM pulse width between 1ms and 2ms thus making it turn all the way to its max angle or min angle, or you can have 1.5ms to stay in center. And also from what i read, you can DAMAGE servo if providint PWM pulse width outside of those specs.
However, i have that Lynxmotion AL5D thingy just recently, and I have HS-645MG attached to its hand, and when with default software I drive it to max/min angles (which is +/-90 degrees) I decided to hook up my logic analyzer to see the pulse widths driven by SSC-32U and here what i found:
all the way + 90 deg: 2.4ms
center: 1.6ms
all the way -90 deg: 0.4ms
isnt it operating outside of specs now?
Hi,
Most hobbyist-grade servomotors allow for a range of at least ±45 degrees from the center position, which is usually at 1.5 ms (or 1500 us). Then, in most cases, they define a rotation direction (CW or CCW) of a certain amount of degrees being mapped linearly to a certain pulse width delta, for example:
]Center at 1500 us, CW rotation 45 degrees at +450 us./:m]
For such an example, you would get a range of 1050-1950 us for a range of 90 degrees of rotation (±45 degrees). In the case of most Hitec servomotors, you get an extended range (±~85 degrees), which gives you very near to a full range of rotation of 180 degrees (a bit less in practice).
To achieve this while still being compatible with the regular controllers that only support 90 degrees of rotation, these servomotors accept a pulse width range larger than the standard 1-2 ms / 1000-2000 us.
When experimenting with servomotors to test their range, just be careful by simply listening to it. If you send a specific pulse width that may be out of range, listen to your servomotor’s sound. If it sounds like it is blocking / stalled, simply disconnect it and try a different pulse width until it doesn’t block anymore. You can determine the range incrementally that way. You could also contact the manufacturer to obtain a datasheet for the specific range of that servomotor. 
Sincerely,
