Yes, many Moxa cellular (OnCell) routers support serial interfaces (RS‑232 / RS‑422 / RS‑485), in addition to Ethernet.
For example:
The Moxa OnCell G4302‑LTE4 includes one serial port (DB9) that supports RS‑232, RS‑422, and RS‑485 standards, with baud rates from 300 bps up to 921.6 kbps. Those serial ports can operate in different modes: real COM port, RFC‑2217 (serial‑over‑TCP), TCP/UDP client or server, so you can connect legacy serial devices over the cellular router to a remote Ethernet or IP network.
In short: if you need to connect legacy serial devices (PLCs, sensors, meters, etc.) over cellular or remote networks, Moxa OnCell routers often provide the needed serial interface; check the datasheet of the model for exact serial‑port support.