Does the Treo Use a SIM Card?

GSM Treos

• Any Treo smartphone device that was released on a GSM network utilizes a SIM card to store the phone's user and carrier information. This includes the Treo Pro, Treo 750, Treo 680, Treo 650, Treo 600, Treo 500, Treo 270 and Treo 180, which were either released as unlocked phones tied to no specific carrier or carrier-locked phones that must be unlocked before being used with another carrier.
  
  

SIM Card Locations

• The SIM card location for these phones varies depending on the model. Most newer models, such as the Treo Pro, Treo 750, Treo 500 and Treo 680, have the SIM card tray located underneath the battery in the phone's battery compartment. Others, such as the Treo 650 and Treo 600, have the SIM card tray located on the top edge of the device near the antenna. Others still, such as the Treo 180 and Treo 270, have the SIM card tray located beneath a SIM door on the backside of the phone. If you own one of the GSM Treos listed, see the supporting document that came with your phone for specific details.
  
  

CDMA Treos

• Any Treo phone released on a CDMA network does not utilize SIM cards in any way. This includes the Treo Pro (which was released on both GSM and CDMA networks), Treo 800w, Treo 755p, Treo 700, Treo 650, Treo 600 (both of which were also released for both carrier types) and Treo 300. For those with Treo devices released on both types of carriers, AT&T and T-Mobile are the largest GSM carriers in the U.S., while Sprint and Verizon are the largest CDMA carriers.
  
  

Treo 90

• The Treo 90 is a handheld PDA rather than a phone and, thus, does not require a subscription to a cell phone plan to use. Since the Treo 90 is not tied to any cell phone carrier, GSM or otherwise, it has no use for a SIM card to store the device's user and carrier information and therefore does not use a SIM card.