HP X.25/9000 User's Guide HP-UX 11i v3 (5900-1523, August 2011)

PAD services and the HP 9000 host
All of the PAD services can be seen as a pipe through which data is passed from X.25 to the PTY
(Pseudo Type) terminal and vice versa (see the illustration below). Terminal data is not modified,
but the X.25 headers are stripped before data reaches the PTY.
Figure 23 PAD services as a pipe
Remote PAD support (x29server)
Overview
The x29server user-level process provides support for communications with terminals attached
to a remote PAD. This process accesses X.25 level 3 through Berkeley Sockets (programmatic
interface) and has an interface to PTYs (see illustration below).
Figure 24 Remote PAD support
The x29server remote PAD support provides capabilities for:
• Managing call acceptance.
• Launching applications automatically.
• Ensuring system security.
• Monitoring access and data transfers.
When x29server begins execution, it examines the PAD support section (pad_spt) of the /etc/
x25/x29hosts file. The PAD support section contains user-configurable parameters for all devices.
See “X.25 Configuration files and examples” (page 144) for an example of the x29hosts file.
Remote PAD support (x29server) 95