Two Atari joystick ports for joysticks or mice Stereo audio RCA connectors ( p-p) A floppy drive port (DB23F), for daisy-chaining up to 3 extra floppy disk drives via a DB23F connector A standard RS-232 serial port (DB25M) A parallel port (DB25F) Power inlet (, ) Analogue RGB PAL and NTSC video output, provided on an Amiga-specific DB23M video connector. Can drive video with HSync for standard Amiga video modes. This is not compatible with most VGA monitors. A Multisync monitor is required for some higher resolutions. This connection can also be genlocked to an external video signal. An RF adapter (A520) was frequently bundled with the machine to provide output on regular televisions or on composite monitors. A digital 16 colour Red-Green-Blue-Intensity signal is available too on the same connector. Monochrome video via an RCA connector Zorro II bus expansion on the left side behind a plastic cover Trapdoor slot under the machine, for RAM expansion and real-time clock Expansions Expansion ports are limited to a side expansion port and a trapdoor expansion on the underside of the machine. The casing can also be opened up (voiding the warranty), all larger chips are socketed rather than being TH/SMD soldered directly to the motherboard, so they can be replaced by hand. The CPU can be upgraded to a Motorola 68010 directly or to a 68020, 68030 or 68040 via the side expansion slot or a CPU socket adapter board. The chip RAM can be upgraded to directly on the motherboard, provided a Fat Agnus chip is also installed to support it. Likewise, all the custom chips can be upgraded to the ECS chipset. The A500+ model instead allowed upgrading by trapdoor chip RAM without clock, but there was no visible means on board to map any of this as FAST, causing incompatibility with some stubbornly coded programs. There were modification instructions available for the A500 to solder or socket another RAM on the board, then run extra address lines to the trapdoor slot to accommodate an additional of fast or chip RAM depending on the installed chipset. Up to of "fast RAM" can be added via the side expansion slot, even more if an accelerator with a non-EC (without reduced data/address bus) processor and 32-bit RAM is used. Hard drive and other peripherals can be added via the side expansion slot. Several companies provided combined CPU, memory and hard drive