6. Device Definition Descriptions

6.1 Local non-SNA 3270 Devices

6.1.1 Function

The local non-SNA 3270 device statements are used to define terminals to the Hercules configuration.
There are no required arguments for this particular device type but there are several optional arguments
that may be specified.

To use this device a tn3270 client must connect to the host machine via the port number specified on the
CNSLPORT statement. A valid tn3270 device type such as IBM-3278 must be used.

If the tn3270 client software allows it to specify a device type suffix (e.g. IBM-3278@GROUPNAME) then
the suffix can be used to connect to that specific device number, if defined. If no suffix is used then the
tn3270 client will be connected to the first available and defined 3270 device.

If a specific terminal device address is specified via the device type suffix of the tn3270 client software
then it must be eligible to connect at that device address or the connection is immediately rejected. An
alternative terminal device for which the tn3270 client might be eligible will not be automatically selected.

6.1.2 Syntax

Descriptive

[groupname [ipaddr [mask]]]

Diagram

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groupname ¬¬¬ ipaddr ¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬«

¬¬
mask ¬¬

6.1.3 Parameter

devaddr

This is the device address.

devtype

This is the device type. Valid terminal device types are 3270 and 3278.

groupname

If a terminal group name is given on the device statement then a device type suffix
with this group name can be used to indicate that a device in this group is to be

used. If it is specified as a terminal type suffix (e.g. IBM-3278@GROUPNAME) and
there are no devices defined with that group name or no available devices remain-
ing in that group then the connection is rejected. If no group name is specified as a
terminal type suffix then the connection will only be eligible to terminal devices
which also have no group name specified.

The terminal group name should be 1-8 alphanumeric characters in length, the first
character being alphabetic and it should not be a hexadecimal number. Upper and
lower case letters in the group name are considered to be equivalent.

The asterisk is used to indicate any terminal group name. It may be omitted if there
are no additional arguments following the group name. If an IP address (and op-
tionally mask) is specified and there is no specific group name desired then the
asterisk must be coded to distinguish the terminal group name and the IP address
arguments.

ipaddr [mask]

The optional IP address and subnet masks specify the IP address(es) at which
client(s) are allowed to connect via the device address identified by the device
statement. This provides an additional means of specifying which device(s) a client
tn3270 session may connect to.

If the IP address and mask (default 255.255.255.255 if not specified) of the tn3270
client attempting to connect match the IP address/mask entered on the device
statement, then the client is eligible to connect at this device address. Otherwise
the client is ineligible to connect at this device address and the next available de-
vice, if any, for which the client is eligible to connect, will be attempted.

If no permissible terminal devices remain (terminal devices for which the client is
eligible to connect) or there are no more available terminal devices then the client
connection is rejected.

The optional IP address and subnet mask may be specified in conjunction with the
terminal group argument. In this case the terminal group argument must be speci-
fied ahead of the optional IP address and subnet mask arguments. To specify an IP
address and a subnet mask without also specifying a terminal group use an aste-
risk (“*”) as the group name substitute or placeholder.

If an IP address / mask are not specified then any client tn3270 session is allowed
to connect to the device (provided they are also a member of the specified terminal
group, if any).

The terminal group name must match if specified, regardless of any optional IP
address / mask. To summarize, the device number suffix always takes precedence
over any group name and any group name always takes precedence over any IP
address/mask value.