6530 Programmer's Guide
Overview
1-12
6530 Programmer’s Guide
TERMPROCESS, ATP6100, SNAX, SNAX6600, X25AM, and WS6530 
are I/O processes or access methods that manage and control the 
communications link. The I/O processes handle data blocking and 
establish the communications protocols required. For the most part, the 
communications interface is transparent to your application. 
1. The 6530 responds with either an ACK or NAK control character 
depending on whether the LRC is good or bad. If the request is to 
enter the same mode that the terminal is already in, the ACK or NAK 
is still sent, but no other action occurs.
2. On a NAK, the host retransmits the mode-switch message.
3. On an ACK, the mode switch completes with the 6530 ready to 
receive data from the host.
6530 Initialization 
Sequences
The 6530 starts operation in the mode selected by the mode configuration 
parameter. Usually, this should be set to conversational mode when the 
workstation or PC is connected to a NonStop host.
When the mode configuration parameter is set to conversational mode, 
the 6530 transmits two control characters, ENQ (05H) and CR (0DH), to 
the host to indicate that the 6530 has been started. The user can then log 
on to the host and access application programs.
On a NonStop host system, your application program can switch modes 
by issuing a SETMODE 8 file system procedure call. The I/O process 
handles the protocol required to ensure a smooth transition between 
modes. The mode-switching protocol is as follows:
Table 1-3. Emulator Connections
Emulator Host Description
Emulator on 
Multilan
Multilan/
WS6530
Emulator to Multilan link to host system with 
Multilan/WS6530.
Emulator 
with Telnet 
client and 
TCP/IP
Telnet 
server, 
TCP/IP
Emulator with Telnet client and TCP/IP link to 
host system with TCP/IP and Telnet server.
Emulator 
with Telnet 
client and 
SPX/IPX
Telnet 
Server, 
SPX/IPX
Emulator on system with TC/SPX/IPS to host 
system with Telnet Server and SPX/IPX.










