3Com SuperStack II PathBuilder S330 Reference Manual page 18

6 C 1: S D
HAPTER YSTEM ESCRIPTION
The following optional modules are available for use with the PathBuilder S310:
The two-port CBR module services traffic generated by your existing PBXs,
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channels, T1/E1 multiplexers, CSU/DSUs, and video conferencing devices. The
CBR module consists of one V.35/RS-449 and one T1-DSX or E1 interface,
which support both structured and unstructured services, in accordance with
the ATM Forum's Circuit Emulation Service (CES) specifications. The CBR
module provides a smooth migration from legacy CBR service (PBX/voice/video)
to ATM service. It also supports all relevant ATM and T1/E1 standards, ensuring
easy integration of existing equipment into new ATM networks.
The one-port Voice Compression module (VCM) is similar in function to the CBR
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module, but it employs compression algorithms that allow more voice calls to
be placed through the same bandwidth. The VCM's T1-DSX/E1 interface
connects to a PBX trunk, which may use CAS or CCS signaling. Its 24/31 DSO
channels can carry individual voice, fax, modem, or data connections. You can
also bundle multiple DSOs to provide connections for high-rate applications
such as video conference or multiple-link PPP. For CCS, a DSO is used as an
ISDN D-channel for carrying signal messages.
Figure 2 shows the PathBuilder S310, with the optional CBR module installed in
expansion slot 7 and the Voice Compression module in slot 8.
Figure 2 PathBuilder S310 WAN Access Switch
Video/Audio
Codec
V.35/
RS-366
RS-449/
RS-530/
X.21
RS-232
10BASE-T
NMS Console
LAN
PBX
T1-DSX/E1
V.35/
RS-449/
RS-530/
X.21
Router
PBX
T1-DSX/E1
T1/E1