Nortel Circuit Card, Installation Manual, Page: 373 / 908

NT5K21 XMFC/MFE card Page 373 of 906
Circuit Card Description and Installation
Sender and receiver mode
The XMFC/MFE circuit card provides the interface between the system’s
CPU and the trunk circuit which uses MFC or MFE signaling.
The XMFC/MFE circuit card transmits and receives forward and backward
signals simultaneously on two channels. Each channel is programmed like a
peripheral circuit card unit, with its own sending and receiving timeslots in
the network.
Receive mode
When in receive mode, the XMFC/MFE card is linked to the trunk card by a
PCM speech path over the network cards. MFC signals coming in over the
trunks are relayed to the XMFC/MFE card as though they were speech. The
XMFC/MFC card interprets each tone pair and sends the information to the
CPU through the CPU bus.
Send mode
When in send mode, the CPU sends data to the XMFC/MFE card through the
CPU bus. The CPU tells the XMFC/MFE card which tone pairs to send and
the XMFC/MFE card generates the required tones and sends them to the trunk
over the PCM network speech path. The trunk transmits the tones to the far
end.
5 900 Hz + 1300 Hz —
6 1100 Hz + 1300 Hz —
7 700 Hz + 1500 Hz —
8 900 Hz + 1500 Hz —
9 1100 Hz + 1500 Hz —
10 1300 Hz + 1500 Hz —
Table 142
MFE Frequency values (Part 2 of 2)
Digit
Forward direction
OG-Tx, IC-Rx Backward direction