3Com 3C501

The 3C501 from 3Com was a very popular Ethernet interface card for early IBM PCs and IBM-compatible PCs.

A 3C501

ETHERLINK (3C501; ASSY.#1221)

NIC Type	Ethernet
Transfer Rate	10Mbps
Data Bus	8-bit ISA
Topology	Linear Bus
Wiring Type	RG-58A/U 50ohm coaxial
	AUI transceiver via DB-15 port
Boot ROM	Available

CABLE TYPE SELECTION

Type	Setting
RG-58A/U 50ohm coaxial	Option 1
AUI transceiver via DB-15 port	Option 2

Configuration jumpers

BOOT ROM CONFIGURATION

Setting	JP3
Disabled	Pins 2 & 3 Closed
Enabled	Pins 1 & 2 Closed

I/O BASE ADDRESS SELECTION BOOT ROM CONFIGURATION

Address	JP4	JP5	JP6	JP7	JP8	JP9
300h	Pins 2 & 3	Pins 2 & 3	Pins 2 & 3	Pins 2 & 3	Pins 1 & 2	Pins 1 & 2
310h	Pins 1 & 2	Pins 2 & 3	Pins 2 & 3	Pins 2 & 3	Pins 1 & 2	Pins 1 & 2

Note: Pins designated should be in the closed position.

BOOT ROM ADDRESS SELECTION

Address	JP12	JP13	JP14	JP15	JP16	JP17	JP18	JP19
CC000h	Pins 2&3	Pins 2&3	Pins 1&2	Pins 1&2	Pins 2&3	Pins 2&3	Pins 1&2	Pins 1&2
EC000h	Pins 2&3	Pins 2&3	Pins 1&2	Pins 1&2	Pins 2&3	Pins 1&2	Pins 1&2	Pins 1&2

Note: Pins designated should be in the closed position.

INTERRUPT REQUEST SELECTION

IRQ	JP20	JP21	JP22	JP23	JP24	JP25
2	Closed	Open	Open	Open	Open	Open
3	Open	Closed	Open	Open	Open	Open
4	Open	Open	Closed	Open	Open	Open
5	Open	Open	Open	Closed	Open	Open
6	Open	Open	Open	Open	Closed	Open
7	Open	Open	Open	Open	Open	Closed

DMA CHANNEL SELECTION

Channel	JP26	JP27	JP28	JP29	JP30	JP31
DMA1	Closed	Open	Open	Closed	Open	Open
DMA2	Open	Closed	Open	Open	Closed	Open
DMA3	Open	Open	Closed	Open	Open	Closed