Enterasys Networks CSX6000 - Manual (Page 61)

Central Site Remote Access Switch 61
H ARDWARE O VERVIEW
System Adapters
P RIMARY R ATE A DAPTERS
Primary Rate is a communications service that provides up to 23 B channels for data and a 64Kbps
signaling D channel (for North America and Japan), or up to 30 B channels for data and a 64 Kbps
signaling D channel. The system uses the B channels for switched connections to carry device data.
The CyberSWITCH supports the following Primary Rate adapters:
•
PRI-8
• PRI-23
• PRI-23/30
These adapters are described in the following discussion.
T HE PRI-8
The PRI-8 adapter provides a single primary rate port that the CyberSWITCH uses to connect to
other CyberSWITCHes. This adapter can take advantage of services such as BOC's and IEC's ISDN
primary rate, or NTT's INS-1500.
Using one PRI-8, up to 8 B channel connections can be active at the same time, to the same or
different destinations. Up to three expander adapters can be used with one PRI-8 to gain 8 B
channel connections per Expander, creating a total of 30 possible connections per line (with one
channel is used for a data link). Only two expander adapters are needed for 23 channels. A TDM
BUS is used to connect the Expander adapters to the PRI-8.
The PRI-8 provides a 4-wire S/T interface. It uses external Channel Service Units (CSUs) to connect
to the public ISDN (when necessary). No external ISDN terminal adapters are needed.
In Japan, NTT provides a dedicated service called High Speed Digital-I that uses the same primary
rate adapters. This can be used at rates from 192Kbps to 1536Kbps. The PRI-8 adapter supports up
to eight HSD-I circuits.
Hardware Characteristics
Processor: Intel 80C186
Speed: 16 Mhz
Number of Ports: 1
Connector: RJ-45
Interface: Point-to-Point
MTBF: 75000hours
MTTR: 0.25hour
T HE PRI-23
The PRI-23 adapter uses an HDLC controller that provides up to 23 HDLC channels on a single
adapter. Up to six PRI adapters can be placed in one system.
The PRI-23 adapter provides support for all available data channels on the primary rate interface.
Used in North America and Japan where primary rate ISDN runs over T1 framing, it provides
support for all 23 available data channels. When used in dedicated line configurations, it supports
up to 24 T1 channels.