The iDCS is sometimes plagued by remote not working, early cabinets caused problems as well as IOM boards, LAN cards, the Modem itself and the MCP card.

If you can call the modem internally and it answers with fax like tones then this is a good start.

Make sure you have the latest version of PCMMC too as there has been so fixes here as well.

Program port 5 in MMC 804 for PCMMC and choose the same Baud rate as you are selecting in PCMMC.

If you still have problems then it is likely there is a hardware fault.