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The Cisco 811 and 813 routers connect small professional offices or telecommuters over Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) lines to corporate local area networks (LANs) and the Internet. The routers offer multiprotocol routing between LAN and WAN ports.
The ISDN BRI service provided by your telephone service provider offers two bearer channels (B channels) and one data channel (D channel). The B channel operates at 64 kbps and carries user data. The D channel operates at 16 kbps and carries control and signaling information, although it can support user data transmission under certain circumstances.
The Cisco 811 and 813 routers include both the ISDN U and ISDN S/T ports.
The ISDN U interface is a two-wire interface from the telephone switch that supports full-duplex data transfer over a single pair of wires. The Cisco 811 and 813 ISDN U interface supports the data service unit (DSU) feature that is integrated in the routers.
The ISDN S/T interface is a four-wire interface from the telephone switch that supports full-duplex data transfer over two pairs of wires. Telephone service providers typically provide an ISDN S/T interface. The Cisco 811 and 813 ISDN S/T interface supports the connection to an external DSU, from which you can connect a digital telephone and other network devices.
The Cisco 813 router supports data and voice applications. The data applications are implemented through the ISDN port. The voice applications are implemented with ISDN BRI and through the telephone ports.
Figure 1-1 shows an example of a network connected to a Cisco 813 router.

Table 1-1 summarizes the features of the Cisco 811 and 813 routers.
| Feature | Description |
|---|---|
10BaseT Ethernet ports | Connects to 10BaseT (10 Mbps) Ethernet networks, compatible with 10/100-Mbps devices. |
Connects to terminal or PC for software configuration using command-line interface and for troubleshooting. | |
Connects to ISDN S/T network. | |
Connects to ISDN U network. | |
Connects to telephone, fax machine, or modem, which are connected to telephone services through ISDN line. | |
Flash memory | 4 MB of Flash memory1. |
Dynamic RAM (DRAM) | 8 MB of DRAM2. |
Easily distinguishable ISDN B-channel LEDs | ISDN B-channel LEDs in a different color from other LEDs. |
Ease of installation | Color-coded ports and cables to reduce the chance of error. |
Cisco IOS software | Supports Cisco IOS software. |
A basic configuration tool for Windows 95, Windows 98, and Windows NT. | |
Locking power connector | Locks power connector in place. |
Wall-mount feature | Brackets on router bottom provide a way to mount router on wall or vertical surface. |
| 1An additional 8 MB of Flash memory can be added at the factory or at your site. You can order an upgrade kit and have trained and qualified personnel add the memory. 2An additional 8 MB of DRAM can be added at the factory or at your site. You can order an upgrade kit and have trained and qualified personnel add the DRAM. |
Figure 1-2 and Figure 1-3 show the front panel of the Cisco 811 and 813 routers.


Table 1-2 summarizes the function of each LED:
| LED | Color | Function |
|---|---|---|
OK | Green | On when power is supplied to the router and when the router completes the self-test procedure and begins operating. |
PHONE 2, 1 | Green | Cisco 813 router only. On when basic telephone service is in use. |
ISDN DSU | Green |
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ISDN LINE | Green | On when the ISDN interface and the ISDN terminal device are synchronized. |
ISDN B1 | Orange |
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ISDN B1 RXD | Orange | Blinks when packets are received from the first ISDN B channel. |
ISDN B1 TXD | Orange | Blinks when packets are sent from the first ISDN B channel. |
ISDN B2 | Orange |
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ISDN B2 RXD | Orange | Blinks when packets are received from the second ISDN B channel. |
ISDN B2 TXD | Orange | Blinks when packets are sent from the second ISDN B channel. |
ETHERNET | Green | Cisco 813 router only:
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ETHERNET 1 | Green |
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ETHERNET RXD | Green | Blinks when an Ethernet port receives a packet. |
ETHERNET TXD | Green |
The back panel of the Cisco 811 and 813 routers contains the router ports and switches. Figure 1-4 shows the back panel of the Cisco 811 router, and Figure 1-5 shows the back panel of the Cisco 813 router.


Table 1-3 lists the router ports on the back panels of the Cisco 811 and 813 routers:
| Router | Ethernet Ports | ISDN U Ports | ISDN S/T Ports | Telephone Ports |
|---|---|---|---|---|
Cisco 811 | One | One | One | None |
Cisco 813 | Four | One | One | Two |
Switches that control router functions are located on the back panels and system boards of the Cisco 811 and 813 routers.
Table 1-4 describes the switches located on the back panels.
| Switch | Function |
|---|---|
TO HUB/TO PC1 | Determines the device and cable type that are connected to the ETHERNET 1 port:
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Normal/reverse switch. Controls the signals that are sent to the tip and ring wires of the ISDN U interface:
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Controls the access to the ISDN S/T signals of the integrated DSU module:
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| 1Settings for this switch assume that you use a straight-through cable. If you are not using a straight-through cable, see Table 3-1 for more information. |
The S/T termination dip switch is located on the system board of the
Cisco 811 and 813 routers and is not accessible from outside of the router. Figure 1-6 shows the location of the S/T termination dip switch.
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Warning Only trained and qualified personnel should be allowed to install or replace this equipment. |
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Warning Before working on a system that has an on/off switch, turn OFF the power and unplug the power cord. |
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Warning Before opening the chassis, disconnect the telephone-network cables to avoid contact with telephone-network voltages. |
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Warning Do not work on the system or connect or disconnect cables during periods of lightning activity. |

The S/T termination dip switch consists of two buttons that work together to control the termination function of the S/T signals:
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Posted: Thu May 25 13:33:14 PDT 2000
Copyright 1989 - 2000©Cisco Systems Inc.