I know that the Maestro is capable of TTL communication. However, I am at a total loss as to how the dynamixel smart servo needs to be wired, let alone the settings to control it with the maestro.
We do not carry the Dynamixel MX-28T servo and I do not have any personal experience with using it, but from a brief Internet search, it looks like it uses half duplex UART, which requires additional circuitry and a direction signal. You can find more details about it in this Robotis manual.
While it is possible to send TTL serial signals from a script using a Mini Maestro, it would probably be more practical to use something like an Arduino (it looks like there are Arduino libraries available for interfacing with those servos as well). The servo channels on the Maestro do not support UART, so the channel settings (e.g. acceleration, speed, min, and max) will not be applicable to anything you send over UART. To send serial signals from a script, you would use the “SERIAL_SEND_BYTE” command, which removes the top number from the stack, interprets it as a single byte, and sends it to the TTL serial output. If you wanted to use some of the channel settings like acceleration or speed, you might be able to write a script that uses a dummy servo channel to keep track of the position and send TTL serial signals to your smart servo that imitate that position.