Sorry for the delay in responding.
If it's a factory unlocked, I understand that the latest firmware is supposed to support pulse dialing.
I have a couple (okay lots) of the HT701 models from BasicTalk from when Walmart was clearing them out for $1. There's a process - if the unit has never been connected to the internet - to be able to flash the Device with factory firmware, unlocking it. The only thing I've run into with these is that the latest firmware seems to brick the BasicTalk devices - I've gotten them to the next to latest with no issues, but the latest does something that does not permit the devices to connect...
It's been a few months, so it may have been resolved, but I'm staying with what works for now.
Jim