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The VWIC-1MFT-G703 and VWIC-2MFT-G703 not only support unframed G.703 but also support all the features of the other VWICs including
Drop and Insert on the VWIC-2MFT-G703. Additional flexibility is provided on the VWIC-2MFT-G703 with the capability to configure one port
for unframed G.703 while configuring the other for standard framed E1.
Multiplexed Voice/Data Solutions: 2-port T1/E1 Drop and Insert Multiplexer with Integrated DSU/CSU
These 2-port Multiflex VWICs simplify branch office connectivity by enabling a Cisco 2600, 2800, 3600, 3700 or 3800 to consolidate the functions
of a router, a fully managed Drop and Insert Multiplexer, and a fully managed DSU/CSU into a single box. Typically a Drop and Insert multiplexer
is used for channelized (i.e. Time Division Multiplexing [TDM]) integration of voice and data onto a single T1/fractional T1 or E1/fractional E1
connection to the CO. Sharing a line can significantly reduce costs over that of two separate physical lines to the CO. While the normal use is for
voice and data sharing of a T1 or E1 service, the Drop and Insert capability can also be used for video and data, or data and data sharing of the
service (e.g. two routers).
Moreover, the Enhanced Availability Drop and Insert (EADI) feature enhances system availability by allowing the Cisco IOS software to be
reloaded while maintaining time division multiplexing (TDM) switching.
Figure 2. Drop and Insert to Share a T1/FT1 or E1/FE1 Service
To illustrate, consider the example of a PBX with a T1 interface that needs to support a maximum of 10 simultaneous calls. With 24 DS0s in a T1
Service (1.544 Mbps) this leaves 14 DS0s or 896 Kbps of bandwidth for data from the router (14 x 64 Kbps). The number of DSOs assigned for
PBX calls and the remainder that are available for use with router data are fully configurable (statically, not dynamically). In the case of an E1
service 30 DS0s are available for division between voice and router data.
In this example one port of the 2-port Drop and Insert Multiflex VWIC is connected to the PBX and the other port is connected to the CO. The 10
DS0s from the PBX are TDM switched to the “CO port” and this switching is done on the VWIC itself. The configuration of this TDM switching is
flexible so that DS0s on the “PBX port” do not have to be mapped to DS0s with the same timeslots on the “CO port”. The remaining 14 DS0s on the
VWIC “CO port” terminate through the VWIC's backplane connector on the router as a single aggregate channel group. The 14 DS0s are not
individually addressable by the router as a channelized service, but can be split into two or more channel groups. (See Table 2 for specifics.)
The 2-port Drop and Insert Multiflex VWIC is the model included in the 2-port versions of the Digital T1/E1 Packet Voice Trunk Network Module.
The term “drop and insert” is normally used when router data (or data from another data device) is multiplexed with voice calls. A more generic term
for “drop and insert” is “digital cross connect”. Digital cross connecting of voice channels only is supported by the 2-port Drop and Insert Multiflex
VWIC when in the NM_HDV, NM-HD-2VE, or NM-HDV2. For example, a single T1 connection from a PBX to the “PBX port” on the VWIC can
