3com MSR 20-20 사용자 설명서

C

HAPTER

 3: M

ULTIFUNCTIONAL

 I

NTERFACE

 M

ODULES

Step 3: Power on the router. Check the status of the LINK LED on the module 
panel. OFF means the link is in trouble and signal is out of synchronization. In this 
case, please check the link.

MIM-2BSV (MIM-4BSV) is short for 2-port (4-port) ISDN BRI S/T voice interface 
module, which is mainly used to process ISDN voice traffic. In the upstream 
direction, it can be connected to user interfaces on an ISDN switch to receive and 
decompress, compress and transmit ISDN BRI digital voice traffic. In the 
downstream direction, the card can be connected to TE devices to allow their 
voice traffic to be forwarded through a WAN interface on the router to the 
Internet, thus implementing VoIP. The interfaces on the MIM-2BSV/MIM-4BSV 
module are ITU-T I.430-compliant, adopting pseudo-ternary coding, providing 192 
Kbps rate, and allowing the maximum transmission distance of 1 km (0.6 mi.) in 
point-to-point mode. MIM-2BSV/MIM-4BSV has the following features.

■

The BSV interfaces support two modes: user and network, respectively for 
connecting an ISDN network and a TE device.

■

When a BSV interface works in network mode, traffic is processed as follows: 
The digital voice traffic received on the BSV interface is compressed and 
forwarded through the CPU on the main control board to a WAN interface. 
The IP voice traffic received on a WAN interface is forwarded through the CPU 
on the main control board to MIM-2BSV/MIM-4BSV, where the traffic is 
decompressed and sent to the TE device.

■

When a BSV interface works in user mode, traffic is processed as follows: The 
digital voice traffic received from the B channels on the BSV interface is 
decompressed and forwarded through the CPU on the main control board to a 
local FXS or FXO analog voice interface. The voice signals received on the local 
FXS or FXO analog voice interface are processed by VoIP and forwarded 
through the CPU on the main control board to the MIM-2BSV/MIM-4BSV 
module, where the traffic is compressed and sent out of the BSV interface to 
the connected ISDN switch.

■

Working in conjunction with the FXS or FXO analog voice interface modules, 
MIM-2BSV/MIM-4BSV provides flexibility in voice call routing.

■

The signaling on the ISDN BRI D channel is processed separately on CPU.

■

The BSV interfaces support remote power supply and thus can be directly 
connected to ISDN phones.

■

MIM-2BSV/MIM-4BSV is dedicated to voice applications, which is different 
from the BS interface cards where BRI data applications are supported.

Table 94   Interface attributes of MIM-2BSV/MIM-4BSV

Connector RJ45 

Number of connectors 

2 

4 

Interface standard 

ITU-T I.430, Q.921, Q.931