Cisco PA-2CT1 Installation And Configuration Manual page 8

What Is the 2CT1 Port Adapter?
When running ISDN PRI, each 2CT1 interface provides 23 bearer (B) channels that can transmit and
receive data at the rate of 64 kbps, full-duplex, and one data (D) channel that can transmit and receive
data at the rate of 16 kbps, full-duplex. The B channels are used for transmitting user data. The D
channel is used for call setup control and network connection teardown, and provides the
communication from the router to the ISDN switch. The B and D channels are presented to the
system as serial interfaces that support High-Level Data Link Control (HDLC) and Point-to-Point
protocol (PPP) encapsulation. The 2CT1 port adapter supports dial-on-demand routing (DDR) when
running ISDN PRI.
Port Adapter Locations on the VIP2 and in Cisco 7200 Series Routers
This section provides information about where you can install the 2CT1 port adapters on the VIP2
and in Cisco 7200 series routers.
Note
occasionally not shown in this publication to highlight port adapter faceplate detail.
Figure 2 shows a VIP2-15 or VIP2-50 with two installed port adapters. Figure 3 shows a VIP2-50
with two installed port adapters. With the VIP2 oriented as shown, the left port adapter is in port
adapter slot 0, and the right port adapter is in port adapter slot 1.
Figure 2
SRAM
DIMM U5
8 Channelized T1 Port Adapter Installation and Configuration
Port adapters have handles that allow for easy installation and removal; however, they are
Two Port Adapters on the VIP2-15 or VIP2-40 (Horizontal Orientation Shown)
Bus connector
Port adapter
in slot 0
CPU Boot ROM
U6
U2
U4
DRAM
SIMMs
Port adapter
in slot 1