I did a little homework this week and wanted to give an update on PCMD.

Sprint I spoke to a Manager in Subpoena Compliance that advised me they do retain PCMD (Per Call Measurement Data). He stated it is only a tool, but it can be an effective tool along with the accompanying cell site data. He stressed that it is NOT Historical GPS. He also stated PCMD accuracy can be affected by the handsets range to the tower, attenuation, geography and the lack of other towers in the area. They retain the data from 5 to 7 days and it rolls off.

Verizon My contact in their LERT was much more optimistic. He stated it will normally narrow down the position of the handset within a tenth of a mile. I asked if there were any variable that might affect the reliability of the data and he stated he has never heard of the data being affected. They also keep the data from 5 to 7 days. The PCMD report with Verizon is called a RTT and this data can be provided if only an SMS was sent. I asked if Verizon could provide an expert witness to testify as to the accuracy of PCMD and I was told Verizon does not provide expert witnesses, but they could provide listings of expert witnesses if necessary.

I just got off the phone with another Verizon analyst. She expressed the same concerns as the guy from Sprint. I had a feeling he was overstating things a bit

Cricket Nothing, but that was not a surprise.

AT&T One of their LERT analysts told me they didn’t have the capability to obtain PCMD. I’m not saying they are wrong, but I find this surprising and would like to speak with another contact at AT&T. AT&T has timing advance.

T-Mobile I’m working on it. 8) T-Mobile does not support PCMD. PCMD is specific to the CDMA service providers, but T-Mobile does have additional ranging data called timing advance. I understand it is difficult to obtain this data. I believe it would be a safe assumption that this data would also only be retained several days before rolling off.