To identify component properties that belong to Allegro device files as
properties, the DEV keyword may be specified in the AttPassList section
of the .cfg file.

To have the PCB interface reflect an alternate package for a given
instance of a part and call the alternate package into the Allegro
layout, add the following lines to the General section of the
allegro14.cfg or allegro15.cfg file:

DoAlternates yes | [no] | Enables the ALTs processing

This generates a .adc file.

In the BeginAttPassList section, add the following lines:

PKG ALT_PKG

PKG ALT_DEV

PKG ALT_TAG

In the BeginChkRules section modify or add the following lines:

CHKBRD _REF_CONFL WRN 1 | REFDES has conflicting properties, 1=repack

CHKVAL _NAME_CHK COM ALT_TAG ERR 0 "a-zA-Z0-9" " " 1 *

CHKVAL _NAME_CHK COM ALT_PKG ERR 0 "a-zA-Z0-9" " " 1 *

CHKVAL _NAME_CHK COM ALTDEV ERR 0 "a-zA-Z0-9" " " 1 *

You can then add the ALT_TAG, ALT_PKG, and ALT_DEV properties to
components.