Not sure if there is a better reason, but I think things like this just end up sticking around due to ossification. Almost anything (desktop/embedded OS, router

Not sure if there is a better reason, but I think things like this just end up sticking around due to ossification. Almost anything (desktop/embedded OS, routers, ..) with a PPP stack will be built to work with modems with AT command sets, so new modems built to handle a PPP stack will still end up implement AT commands. Meanwhile if it's not broke, why fix it? It looks like the ATDT command has worked since 1981. All of at least Huawei's 3G/4G dongles still support this mode, and would expect it's the same for pretty much any other vendor.