I have a call center with nortel 3905 ACD phones and Plantronics CS 50 and CS 55 wireless headsets w/ no handset lifters. The problem is some of the headsets notify the user with an notification of a caller and some cannot hear if a call is coming in thru the headset. They appear to be configured the same way, what I am missing?

SOURCE: CS70N Wireless headset

The earpiece will make 3 short beeps when a call is incoming. Also the phone will still ring if you are within distince to hear the ringer. Hope this helps! SM

SOURCE: Plantronics cs50 head set with lifter has STATIC

Try a system reset:
1.  Lift the headset off of the charging cradle, but make sure the headset is turned off.  It will be off if the green light on the front of the base is not lit.  If it's not, push the call answer button once to turn it off.
2.  Push the call answer button and the mute button at the same time and hold them down.  The mute button is the black little wheel at the top of the headset.  Use the tip of your finger to push it straight down and hold it while holding the call answer button.  A green light on the headset will flash for 2 series of flashes.  Wait until the end of the second series then let go of both buttons.
3.  Put the headset back on the charging cradle and wait 30 seconds.  Lift it back up and try to use it.  If this doesn't work, repeat one more time and then disconnect the power from the base and plug it back in.

SOURCE: outside caller hears themselves in an echo

Echo is usually caused by the transmit (speak) level on the unit being set too high.

1. First, try lowering the volume of the telephone. If you still hear an echo, adjust the volume of the headset itself.

2. The master transmit controls of the headset are the ABCD switch settings on the bottom of the base. A is the lowest and D is the highest setting.

3. You can fine tune this setting with the plus (+) and minus (-) buttons on the back of the charging base.

4. If this doesn't fix the echo, try moving the configuration dial on the left side of the charging base. The recommended setting for most phones is 1.

SOURCE: plantronics cs55 problem

Turn on the wireless headset as soon as the HL10 lifter picks up the headset. Remember to press the call answer switch. A steady green light should come on the base and the wireless headset should have a small green blinking light on, on its side.

* Make sure your hand receiver is off the hook when using the headset. Also check that you hear a dial tone on the handset/hand receiver before turning on the headset.

SOURCE: All of a sudden my

If the Plantronics CS55 wireless headset shows that it is on, you have to make sure of the following things.

a. the green LED on the base turns on when you turn the call switch on from the headset.
b. the small green LED on the side of the headset is blinking.
c. the telephone headset is lifted from the cradle.
d. if the headset is not charging and the Amber light on the base does not blink when you place wireless headset on it; trying placing the headset more firmly.
e. If the headset is not charging and the Amber light on the base does not blink even after placing the wireless headset firmly on the charging cradle, you may need to change the battery.

Alternately you can try resetting the Plantronics CS55 wireless headset.

Reset Plantronics CS50, CS60 or CS55 Wireless Headset

If you have problems with the sound or connection of your Plantronics CS50, CS60 or CS55 wireless phone headset, you may want to try to hard reset it using the following steps:

Note: Ensure the IntelliStand switch (on the right side of the charging base) is in the - position and NOT the = position.

1. Press both the call control button and the listening volume/mute button for 5 seconds. When the indicator light blinks release both buttons.

2. Press the call control button again. The talk indicator light will again blink to indicate the headset is back to normal.

3. Disconnect the AC charger from the AC charging jack for 5 seconds.

4. Reconnect the AC charger.

Now give the Plantronics headset a try.