Device characteristics field

The device characteristics field (see IDSDVCHR in Control block formats and DSECTs) contains only limited information about a 3270 LU. It contains the model number specified in the FEATUR2 network definition operand for the 3270 terminal (refer to z/OS Communications Server: SNA Resource Definition Reference for information on operands). Use this model number to derive a default display screen size or the buffer size for the terminal. The preferable way to determine this default, however, is to use information that can be supplied in the presentation-services field of the session parameter as described in the preceding section.

Also usually available in the device characteristics field is the physical device address needed as the “from” address for the 3270 copy function. Also, the copy function is not supported by channel-attached 3270s.

The field labeled DEVTCODE in the device characteristics field should not be used to attempt to determine the device type of the terminal. All 3270 terminals should be considered to be LUs and the DEVTCODE field must be ignored.