The A2065 is a full-length Zorro-II network card that supports the Ethernet
standard. Both BNC (coax) and DB15 (AUI) connectors are provided. While the
A2065 hasn't been produced for some time, it's still the most common
Ethernet board found in Zorro-bus Amigas.
10Base-2 (coax cable, or "thin net") and 10Base-T (twisted pair) are now
the most common variations of Ethernet.
Thin Net (10Base-2, or coax)
The coaxial cable variant of Ethernet uses a bus arrangement, where a
"t-connector" is attached to the BNC connector of the Ethernet board, and
RG58 coaxial cable is connected to the two BNC connectors on it. (Note that
"stub" extension cables between the t-connector and the card are *not*
allowed.) At the ends of the bus, 50-ohm terminating resistors are
installed on the unused BNC connectors of the t-connector.
Twisted Pair (10Base-T)
Twisted-pair Ethernet uses two pairs of Category 3 (or higher) twisted-
pair wire, although the wire usually used actually contains four pairs.
Eight-conductor RJ45 phone-type connectors are used (the actual pins
connected are 1,2,3 and 6). Topologically, 10Base-T uses a star
arrangement, where wire is run between each workstation and a
"concentrator," or hub. Two cards can be directly connected with a "null-
modem" version of the standard cable, in which the pairs are swapped (1-2
connect to 3-6, and 3-6 connect to 1-2).
While the A2065 does not directly support 10Base-T, inexpensive
transceivers are available to plug into the AUI port.
The firmware Ethernet address of the A2065 can be determined by taking the
registered CBM block number (00-80-10) and appending the hex value shown on
the sticker on chip U4.
| |_| BNC
| JP7 ABC |_
| : ABC | |
| ABC | | AUI
| JP1-JP6 | |
| :::::: |_|
JP1-JP6: Interrupt (default is JP2).
JP7: Ethernet Type
Off: Type 1.
On: Type 2 (default).
ABC Jumpers: Select Thick/Thin Ethernet.
AB: Select BNC connector (thin Ethernet).
BC: Select AUI connector (thick Ethernet).
Converted on 02 Jun 1997 with RexxDoesAmigaGuide2HTML 2.1 by Michael Ranner.