Juniper Allegro CE Owner's Manual page 59

PCMCIA stands for the Personal Computer Memory Card
International Association. This association has developed standards for
PC cards. PC cards are about the size of a credit card and come in
three thicknesses or types.
The PC card slot accepts Type I or Type II cards. These cards include
ATA Flash cards, SRAM (Static Random Access Memory), and
Compact Flash adapter cards. All types of cards have a 68 pin
connector for attachment to the Allegro. The cards must be 5 V or 5 V/
3 V (PC cards that are 3 V only are not supported). This is a 16 bit
card slot. It is not a "card bus" slot.
A PC memory card is a solid state, self-contained memory board
housed in a credit card-sized package. These cards behave like hard
drives. You can read from them, write to them, and erase single files
from them. There are several types and brands of cards available.
ATA Flash Cards
ATA Flash cards provide solid state data storage. Power is not
required to maintain the data, and because of this feature, we
recommend them over other types of memory cards. The Allegro
accepts cards ranging in size from 1 M to 100+ M, with larger cards
available.
Formatting ATA Flash Cards
ATA Flash cards come pre-formatted.
Memory and Data Storage Page 3-5