B128

The CBM-II models were Commodore's last effort to capture the business market with it's superior proprietary technology. This line actually did fairly well in the small business realm, but was eventually scrapped for the PC-clones. This line includes the B500, B128, B256, B128-80HP, B256-80HP in the U.S., and the CBM 500, 610, 620, 700, 710, and 720 in Europe. The 610 and 620 correspond to the B128 and B256 respectively, while the CBM 710 and 720 correspond to the B128-80HP, and B256-80HP respectively.

All the machines in this line are distinguished by the MOS 6509 processor, Commodore BASIC 4.0 (like that found in the later CBM/PET computers, the Commodore "SID" sound chip, an RS232-C port, IEEE-488 peripheral compatibility, and 80 column text video capability. Shown here on the right is the 128k B128 computer.

The B128, B256, B500, CBM 500, CBM 610, and CBM 620 constitute the "Low Profile" CBM-II machines. A single integrated unit featuring a full business keyboard, numeric keypad, and 12 function keys. The B128 pictured above includes 128K of banked memory (64K maximum in each bank).

Statistics, features, and B128 resources:

CPU: MOS 6509

• 2 mhz

RAM: 128 Kilobytes

• Expandable to 256k internal, 704k external

ROM: 24 Kilobytes

• B128 Kernal
  • (Download image)
• CBM Basic 4.0
  • 128k (B128) Basic ROM Low(Download image)
  • 128k (B128) Basic ROM High(Download image)
• Character ROM(Download image)

Video: MOS 6545 CTRC

• Text: 80 columns, 25 rows.

Sound: MOS 6581 SID

• 3 voice stereo synthesizer/digital sound capabilities

Ports: CSG 6551/6525x2/6526

• Male edge-connector IEEE-488 port
• Male edge-connector CBM Datasette port
• Female RS232 port
• Round DIN CBM Monitor port
• Female edge-connector CBM-II/PET-II expansion port
• 1 RCA audio port
• Power and reset switches

Keyboard: Full-sized 102 key QWERTY

• 19 key numeric keypad!
• 4 direction cursor-pad

Resources

• 28 pin EPROM adaptor info
• CBM-II power supply information

Personal Note:The CBM-II line are personally very cool to me. I used to sit and write little BASIC programs on these things, but they fell out of favor as my collection grew, so now they are all boxed up. The B128 I acquired on a tip from another collector.

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