For the u-blox SARA-R500S and SARA-R500E the S signifies a SIM card is needed and the E signifies that it contains an eSIM. The S has global options, while the E is North America on AT&T.
Here are the block diagrams. Source u-blox data sheet.
For the u-blox SARA-R500S and SARA-R500E the S signifies a SIM card is needed and the E signifies that it contains an eSIM. The S has global options, while the E is North America on AT&T.
Here are the block diagrams. Source u-blox data sheet.