Introduction to Networking for NonStop S-Series Servers

Device-Specific Connections

Introduction to Networking for HP NonStop S-Series Servers—520670-005

6-6

X.25 PSDN Connections

You can connect NonStop S-series servers with other systems and devices, including

asynchronous terminals, on an X.25 packet-switched data network (PSDN) by using

X25AM. X25AM supports full-duplex communications. Each X25AM line can support

approximately 230 active connections; multiple terminals can be supported through a

packet assembler/disassembler (PAD), which then connects to a NonStop S-series

server through a single line. X25AM is described in Section 8, Open Systems

Interconnection (OSI) Network Connections.

X3PAD helps you to connect asynchronous terminals with X25AM. X3PAD is a

software application that emulates a conversational terminal attached to a PAD. It

allows a terminal connected to a NonStop S-series server to connect to X25AM

software, which in turn allows access to a system other than a NonStop S-series server

(or other type of NonStop server) across an X.25 PSDN. The terminal can operate only

in conversational mode.

Figure 6-2 on page 6-7 shows terminals connected to remote systems across an X.25

PSDN using X25AM and X3PAD. You can also use X3PAD to transfer information

between a Guardian file and a system other than a NonStop server across an X.25

PSDN. The figure also shows various ways that applications on NonStop S-series

servers can communicate with terminals across an X.25 PSDN. In fact, X25AM can be

configured to communicate with X.25-compatible terminals without an intervening

PSDN.