It will not come on

There is a solution here

https://ivanexpert.com/2011/04/recovering-data-from-an-old-palm-treo-to-a-mac-and-iphone/

More here plus the Apple Support Community.

https://www.google.com/search?q=copy+calendar+from+Palm+Treo+755P+to+iPhone

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You can use the Unlock code to Unlock Your Palm-One Tero 650 model Phone,You can get the Unlock code from here
Wickedunlock and follow the instructions and Unlock it step by step..
Palm One Treo 650 Unlocking InstructionsWarning : Do not enter any wrong unlock codes on your Palm One Treo 650 mobile phones. If you enter over a certain amount of wrong unlock codes on your Palm One Treo 650 mobile phone, your phone may get hard locked and sometimes become unusable.
1 - Switch ON your Palm One Treo 650 with an ACCEPTED SIM Card,
2 - Go to Menu and select "Phone Tool" or "Phone Application",
3 - Type on Virtual Keyboard *#*#CODE#,
4 - Select with PEN "Numer" and Palm One Treo 650 will show that it's unlocked now!

or

1 - Switch ON your Palm One Treo 650 with a NOT ACCEPTED SIM Card,
2 - Enter the Unlock Code we send to you.

or

1. Remove Palm One Treo 650 battery, unplug cable,
2. Switch ON your Palm One Treo 650 with a NOT ACCEPTED SIM Card,
3. 'Sim not allowed' is displayed, click OK,
4. Go to the dial pad, and dial *#*#CODE#,

CODE: The unique unlock code for your Palm One Treo 650.
ACCEPTED : We mean, to use a sim card from the network your Palm One Treo 650 is locked to.
NOT ACCEPTED : We mean, to use a sim card from a network other than the network your Palm One Treo 650 is locked to.

The Treo Pro is a different phone than the 700w. Here are two links to Palm's website with support information on both phones.
http://kb.palm.com/wps/portal/kb/na/treo/700w/verizon/home/page_en.html
http://kb.palm.com/wps/portal/kb/na/treo/t850/alltel/home/page_en.html

You need to download google sync on you're palm treo.

Check the websites below:

Palm Treo 750 Initial Setup

Your Palm Treo 750 Smart Device Getting Started Guide

Palm Treo 750v Smartphone Quick Reference Guide

palm treo 755p doesnt have a sim card tray!

sorry

need a puk code for my palm treo 750

What is happening with the Sync? Does your PC and the Palm Desktop Manager recognize your TREO 600? If not, the issue may be that somehow the driver for your device was removed. I would suggest upgrading to the latest version of the Palm Desktop Manager and try plugging in your TREO 600 again and try synching.

Here is the location for the free software from Palm. http://www.palm.com/us/software/palmsoftware.html

You also have to make sure that the setting on the Palm Desktop Manager is the same as the type of cable you are using. If it is a USB cable, have that setting on your PC's Palm Desktop Manager Hotsync settings.

try restarting the computer. it works for me

Simplest method for 'switchers': Assume that your Treo 600 has the data you need (it does but you are focusing on your Palm Desktop in your question). Install the Palm Desktop software again using the CD but this time, choose the option to synchronize with Outlook during the installation process. This will switch the synchronization to Treo <-> Outlook instalead of Treo<->Palm Desktop. Assuming your Treo is recently synched with Palm Desktop, this will merge the data you have in the Treo with that of your Outlook profile.