3Com 3c509 is a line of Ethernet IEEE 802.3 network cards for the ISA, EISA, MCA and PCMCIA computer buses. It was designed by 3Com, and put on the market in 1994. Features The 3Com 3c5x9 family of network controllers has various interface combinations of computer bus including ISA, EISA, MCA and PCMCIA. For network connection, 10BASE-2, AUI and 10BASE-T are used. B = On ISA and PCMCIA adapter numbers indicates that these adapters are part of the second generation of the Parallel Tasking EtherLink III technology. The DIP-28 (U1) EPROM for network booting may be 8, 16 or 32 kByte size. This means EPROMs of type 64, 128, 256 kbit (2^10) are compatible, like the 27C256. Boot ROM address is located between 0xC0000 - 0xDE000. Teardown example, the 3c509B-Combo The Etherlink III 3C509B-Combo is registered with the FCC ID DF63C509B. The main components on the card is Y1: crystal oscillator 20 MHz, U50: coaxial transceiver interface DP8392, U4: main controller 3Com 9513S (or 9545S etc.), U6: 70 ns CMOS static RAM, U1: DIP-28 27C256 style EPROM for boot code, U3: 1024 bit 5V CMOS Serial EEPROM (configuration). Label: Etherlink III (C) 1994 3C509B-C ALL RIGHTS RESERVED ASSY 03-0021-001 REV-A FCC ID: DF63C509B Barcode: EA=0020AFDCC34C SN=6AHDCC34C MADE IN U.S.A. R = Resistor C = Capacitor L = Inductance Q = Transistor CR = Transistor FL = Transformer T = Transformer U = Integrated circuit J = Jumper or connector VR F FL70: Pulse transformer bel9509 A 0556-3873-03 * HIPOTTED Y1: 20 MHz crystal 20.000M 652DA U50: P9512BR DP8392CN Coaxial Transceiver Interface T50: Pulse transformer, pinout: 2x8 VALOR ST7033 x00: Pulse transformer VALOR PT0018 CHINA M 9449 C U4: Plastic package 33x33 pins Parallel Tasking TM 3Com 40-0130-002 9513S 22050553 AT&T 40-01302 Another chip with the same function: 40-0130-003 9545S 48324401 AT&T 40-01303 U6: 8192 x 8-bit 70 ns CMOS static RAM HY 6264A LJ-70 9509B KOREA Another chip with the same function: CY6264-70OSC (photo) U1: Boot ROM DIP-28 EPROM 8,16, or 32 kB (27/28C256) for boot code. U3: 256 Bit/1K 5.0V CMOS Serial EEPROM B 52AH 93C46 M8 Q41: N-Channel Logic level Power MOSFET 60V, 11A, 107 mΩ (using ASSY 03-0021-004 due to obscured view) F3055L 96 45 (H)H VR41: 3-Terminal 0.5 A Negative Voltage Regulator (-5V) in D2PAK KA79 M05 ASSY 03-0021-004 REV-B has written on it: U.S. Patents: Connector for the computer bus: ISA 16-bit Connections for networking: