User guide

1-5
Cisco H.323 Signaling Interface User Guide
OL-2156-04 Rev. A1
Chapter 1 Cisco H.323 Signaling Interface Overview
Operational Environment
call to the PSTN. In this case, the originating and terminating HSIs establish the call normally but pass
the H.245 address of the H.323 endpoints. This enables the two endpoints to use H.245 to negotiate
media channels with each other directly, independent of the HSI.
T38 Fax
The T.38 Fax feature enables the HSI to alter a call, initially established for voice, to support a fax
transmission.
When a fax call is initiated, a voice call is established. When the terminating gateway detects the fax
tone generated by the terminating fax machine, the gateway initiates a T.38 mode request using H.245
procedures from the terminating gateway. If the opposite end of the call acknowledges the T.38 mode
request, the initial audio channel is closed and a T.38 fax relay channel is opened.
Operational Environment
This section provides operational environment requirements for the Cisco HSI.
Hardware Requirements
The Cisco HSI is targeted to run on a Sun Netra T1 100/105 platform with an 18-GB hard disk drive, a
Sun Netra 120 platform with a 36-GB hard disk drive, or a Sun Fire V120 platform with a 36-GB hard
disk drive. These platforms run on the Sun Solaris 8 operating system.
Software Requirements
The Sun Netra T1 100/105platform, Sun Netra 120 platform, and Sun Fire V120 platform run on the
Solaris 8 operating system.
Security
The application does not directly provide security features. All security must be implemented at the
UNIX level.
Cisco HSI Recovery
The Cisco HSI automatically restarts the main application process if that process terminates.
Cisco HSI System Limitations
The Cisco HSI does not implement security features.