The CBM 256-80 truely represents the top of the CBM-II line.
The stylishly curved plastic case with detachable keyboard and built in monitor are a contrast to the
rest of the CBM-II models, giving it the "High Profile" distinction.
The CBM 256-80 HP is the big brother to the CBM 128-80 HP and was known as the
CBM 720 in Europe.
Like the other CBM-II models, the 256-80 has a full-sized qwerty keyboard, 80 column display,
Commodore BASIC 4.0, RS232-C and IEEE-488 ports, and the ability to attach an optional 8088 or Z-80
The CBM 256-80 HP has an ample 256K of banked memory, and the particular model
in this collection was also lucky enough to include the 8088 coprocessor board
for running MS-DOS programs. MS-DOS compatility was considered an important
feature at the time, as IBM was just beginning to envelope the business computing
The CBM-II High profile machines, which include the CBM 128-80, 256-80,
710, and 720, could all be purchased with built-in disk drives.
These drives are said to be 8050 compatible mechanisms.
Statistics, features, and CBM 256-80 resources:
8088 daughterboard inc
Expandable to 704k external
CBM Basic 4.0
MOS 6545 CTRC
Monitor: 12" Monochrome display
80 columns, 25 rows
MOS 6581 SID
3 voice stereo synthesizer/digital sound capabilities
Male edge-connector IEEE-488 port
Male edge-connector CBM Datasette port
Female RS232 port
Female edge-connector CBM-II/PET-II expansion port
1 RCA audio port
Power and reset switches
Optional cable attachment with IEC serial ports.
Full-sized 102 key QWERTY
19 key numeric keypad!
4 direction cursor-pad
Personal Note:I was astonished to finally get
my hands on this beauty from eBay
auctions. The seller of the 256-80 told me that it was non-functional. He was
wrong. Moreoever, this particular unit contains the EXTREMELY
rare 8088 daughterboard (pictured above).