Configuring Remote CAPI

Overview of CAPI

CAPI Features

CAPI and RVS-COM

Supported B Channel Protocols

Supported D Channel Protocols

Supported Applications

Requirements

Configuring RCAPI

Configuring Remote CAPI

Overview of CAPI

The Common Application Programming Interface (CAPI) is an application programming interface standard used to access ISDN equipment connected to Basic Rate Interfaces (BRIs) and Primary Rate Interfaces (PRIs). Remote Common Application Programming Interface (RCAPI) is the CAPI feature configured remotely from a PC client. CAPI provides the following features:

A standardized interface through which application programs use ISDN drivers and controllers. One application can use one or more controllers. Several applications can share one or more controllers.
A selection mechanism that supports applications that use protocols at different levels and standardized network access. To provide this support, an abstraction from different protocol variables is performed by the software. All connection-related data, such as connection state and display messages, is available to the applications at any time.

Figure 5-1 shows how CAPI connects applications, drivers, and controllers.

Figure 5-1: Remote CAPI Connections

The framing protocols supported by CAPI include High-Level Data Link Control (HDLC), HDLC inverted, bit transparent (speech), and V.110 synchronous/asynchronous. CAPI integrates the following data link and network layer protocols:

Link Access Procedure on the D-channel (LAPD), in accordance with Q.921 for X.25 D-channel implementation
Point-to-Point Protocol (PPP)
ISO 8208 (X.25 DTE-DTE)
X.25 DCE, T.90NL, and T.30 (fax Group 3)

CAPI Features

CAPI supports the following features:

Basic call features, such as call setup and tear-down
Multiple B channels for data and voice connections
Multiple logical data link connections within a physical connection
Selection of different services and protocols during connection setup and on answering incoming calls
Transparent interface for protocols above Layer 3
One or more BRIs as well as PRI on one or more Integrated Services Digital Network (ISDN) adapters
Multiple applications
Operating-systems-independent messages
Operating-system-dependent exchange mechanism for optimum operating system integration
Asynchronous event-driven mechanism, resulting in high throughput
Well-defined mechanism for manufacturer-specific extensions
Multiple supplementary services

Figure 5-2 shows the components of the RCAPI implementation.

Figure 5-2: Remote CAPI Implementation

CAPI and RVS-COM

The router supports the ISDN Device Control Protocol (ISDN-DCP) from RVS-COM. ISDN-DCP allows a workstation on the LAN or router to use legacy dial computer telephony integration (CTI) applications. These applications include placing and receiving telephone calls and transmitting and receiving faxes.

Using ISDN-DCP, the router acts as a DCP server. By default, the router listens for DCP messages on TCP port number 2578 (the Internet-assigned number for RVS-COM DCP) on its LAN port.

When the router receives a DCP message from a DCP client (connected to the LAN port of the router), the router processes the message and acts on it. The router can send confirmations to the DCP clients and ISDN packets through the BRI port of the router.

When the router receives packets destined for one of the DCP clients on its BRI port, the router formats the packet as a DCP message and sends it to the corresponding client. The router supports all of the DCP messages in the ISDN-DCP specifications defined by RVS-COM.

Supported B Channel Protocols

The router provides two 64-kbps B channels to CAPI clients. Each B channel can be configured separately to work in either HDLC mode or bit transparent mode. For CAPI support, layers B2 through B7 protocols are transparent to the applications using these B channels.

The ISDN core engine of RVS-COM supports the following B-channel protocols:

CAPI layer B1
- 64 kbps with HDLC framing
- 64 kbps bit transparent operation with byte framing from the network
- T.30 modem for fax Group 3
- Modem with full negotiation
CAPI layer B2
- V.120
- Transparent
- T.30 modem for fax Group 3
- Modem with full negotiation
CAPI layer B3
- Transparent
- T.90NL with compatibility to T.70NL according to T.90 Appendix II
- ISO 8208 (X.25 DTE-DTE) module 8 and windows size 2, no multiple logical connections
- T.30 for fax Group 3
- Modem with full negotiation
T.30 for fax Group 3 (SFF file format [default], sending and receiving up to 14400 bits/sec with ECM option, modulations V.17, V.21, V.27ter, V.29)
Analog modem (sending and receiving up to 14,400 bits/sec, modulations V.21, V.22, V.22bis, V.23, V.32, V.32bis)

Supported D Channel Protocols

CAPI support is available only for the ISDN switch type Net3.

Supported Applications

ISDN-DCP supports CAPI and non-CAPI applications. Applications are supported that use one or two B channels for data transfer, different HDLC-based protocols, Euro file transfer, or G4 fax; also supported are applications that send bit-transparent data such as A/Mu law audio, group 3 faxes, analog modem, or analog telephones.

Requirements

Before you can enable the RCAPI feature on the Cisco 800 series router, the following requirements must be met:

Cisco 800 series software with RCAPI support is installed on the router.
CAPI commands are properly configured on the router.
Both the CAPI local device console and RCAPI client devices on the LAN are correctly installed and configured with RVS-COM client driver software.

Configuring RCAPI

The following procedure provides step-by-step instructions for configuring RCAPI on the 800 series router:

Step 1 At the local device console, change to global configuration mode.

router# configure terminal
router(config)#

Step 2 Set the switch type. In the following example, the switch type is set to European Telecommunication Standards Institute (ETSI).

router(config)# isdn switch-type basic-net3

Step 3 Enter the RCAPI directory number assigned by the ISDN provider for the device. For example:

router(config)# rcapi number 12345

Step 4 Optional. Perform this step only if you wish to specify a port number for RCAPI functions. Otherwise, the default port 2578 is used. Configure the same number on both the router and client PC. For example:

router(config)# rcapi server port 2000

Step 5 Exit from global configuration mode to interface configuration mode.

router(config)# int bri0

Step 6 Set the switch type for the BRI0 interface. In the following example, the switch type is set to ETSI.

router(config-if)# isdn switch-type basic-net3

Step 7 Set the modem as the default handler for incoming voice calls.

router(config-if)# isdn incoming-voice modem

Step 8 Change to privileged EXEC mode either by pressing Ctrl-Z or by entering exit twice, once at the interface mode prompt and again at the global configuration mode prompt.

router(config-if)# exit
router(config)# exit
router#

Step 9 Optional. Enter the following if you wish to display RCAPI status.

router# show rcapi status

Step 10 Optional. In privileged EXEC mode, start the debug program to run in the background.

router# debug rcapi events

Step 11 If required, at each remote device console, change to global configuration mode. Repeat Step 2 through Step 10 to configure that device.

Table of Contents

Configuring Remote CAPI