Game Link II
From Atariki
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GameLink-II Specification
Copyright (c)1993 DataQue Software
AGDAgon information Copyright (c)1993 The AGDA Group
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Version 1.0 December 27, 1993
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DataQue Software and The AGDA Group assume no responsibility for
damages caused by individuals attempting to make the modifications
described in this document. Please read all instructions carefully!
A) Normal SIO Physical Connections:
1) The GameLink-II serial link uses the SIO bus which is standard on
all Atari 8-bit computer systems.
2) The SIO port is a 13-pin custom connector with the pins defined
as follows:
pin name source function
--- -------- -------- -----------------------------------
1 SCLK PoKey Serial Input Clock
2 OCLK PoKey Serial Output Clock
3 SID PoKey Serial Data Input
4 DGND Power Data Ground
5 SOD PoKey Serial Data Output
6 CGND Power Chassis Ground
7 COMMAND PIA Serial Command
8 MOTCTL PIA Cassette Motor Control
9 PROCEED PIA Interrupt input
10 +5V Power Processor Ready
11 AUDIO IN PoKey Audio in to modulator/PoKey
12 +12V/NC Power Unused on XL/XE
13 INTERRUPT PIA Interrupt input
3) A view of the free end of the SIO connector (the one on your
8-bit computer) would appear as shown below:
----------------------
/ 2 4 6 8 10 12 \
/ o o o o o o \
/ \
/ o o o o o o o \
/ 1 3 5 7 9 11 13 \
---------------------------------
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GameLink-II Docs
4) Note: Unfortunately, every SIO cable we have run across (quite a
few) had different colors for each of the wires. The only wire
that has been consistant is the chassis ground, which has always
been a bare wire (shield drain).
5) The GameLink-II specification does not use all of the SIO lines.
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B) Temporary GameLink-II SIO Connections (2 nodes):
Realizing that users might want to try "Maze of AGDAgon" and the
GameLink II system before committing to building or buying a more
permanent connection, we offer the following directions. Follow
these for a quick, temporary method to connect two Atari 8-bit
computers together.
1) Scrounge up two or three paper clips (the smaller size) and a
rubber band.
2) Bend and cut the clips into the following shapes with the
dimensions shown below. Make sure the cut ends do not have any
burrs, as these could damage your SIO cables.
<--5/8"--> <--5/8"--> <---7/8"--->
---------- ---------- ------------
^ | | | | | | ^
| | | | | | | |
1/2" | | | | | | |
| | | | | | | 3/4"
v | | | | | | |
"A" "B" | "C" | |
| | v
3) Boot up the Host computer, load the AGDAgon.COM file, and
disconnect the serial cable from the disk drive. The other end
of the serial cable should still be connected to your Atari.
4) Get the other Atari ready (monitor or TV connected and turned
on, serial cable plugged in).
5) Take the free ends of the serial cables, and wrap the rubber
band around the two connectors, so that the free ends face you
like the diagram below:
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----------------------
/ C \
/ o o o o o o \
/ \
/ o o o o o o o \
/ A B \
---------------------------------
---------------------------------
\ A B /
\ o o o o o o o /
\ /
\ o o o o o o /
\ C /
----------------------
6) Now take the first of the two smaller clips you made and gently
push it into both pins marked "A" above. If you feel great
resistance, do not try to force the pins in, as you may damage
the connectors on your serial cable. Since the clips you have
made are narrower than the standard Atari pins, they should not
cause damage if inserted correctly. Be careful not to
accidentally short together any other pins.
7) Take the second of the two smaller clips and push it into the
pins marked "B" above. Try to push the two pins in an equal
amount. It doesn't matter if the two clips touch each other.
8) Take the remaining (longer) clip you made and push it into the
pins marked "C" above. Be careful not to short it against any
other pins. The third clip was intentionally made longer so
that it won't be touching the other two clips when installed
correctly.
9) Place this assembly carefully on a table top and out of the way
(don't leave it dangling from the two computers).
10) Turn on the second Atari. It should boot up as described under
the "GAME STARTUP" section of the rules. Enjoy the game!
11) You can play multiple games without having to do this procedure
before each game (read the rules section). Remember to
carefully disconnect the 3 clips from the serial cables when you
are done playing for the day.
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C) GameLink-II SIO Connections (2 or 3 nodes):
The following directions give you some insight into how the GameLink
II system works, and will allow you to create a more permanent
connection for two or three player games. They are provided for the
more technical user who has sufficient experience to assemble a
small hardware project. Non-technical users who wish to buy a
multi-node connection should skip to the next section.
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GameLink-II Docs
1) The easiest way to construct a GameLink-II cable is to purchase
a long (6 foot) SIO cable and cut it in half.
2) If more length is needed, the wires can be extended to around 6
feet per node (thus, from one computer to any other would be a
maximum of 12 feet).
3) The connections are made according to the following list:
pin name connection description
--- -------- ---------- -------------------------------
1 SCLK not used leave with no connection
2 OCLK not used leave with no connection
3 SID PARALLEL connected to all other SID & SOD
4 DGND PARALLEL connected to all other DGNDs
5 SOD PARALLEL connected to all other SID & SOD
6 CGND PARALLEL connected to all other CGNDs
7 COMMAND not used leave with no connection
8 MOTCTL not used leave with no connection
9 PROCEED not used leave with no connection
10 +5V not used leave with no connection
11 AUDIO IN not used leave with no connection
12 +12V/NC not used leave with no connection
13 INTERRUPT not used leave with no connection
4) Both grounds are connected between all systems.
5) Both the SID (Serial Input), and SOD (Serial Output) lines are
connected together from all nodes. This allows any node to
transmit data to all other nodes (including itself, if
desired).
6) A graphical representation of a 3 node GameLink-II network is
shown below, with wires indicated by dashes (-) and vertical
bars (|). Junctions shown by asterisks (*)
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Node-1 Node-2 Node-3
------ ------ ------
SID(3) SID(3) SID(3)
| | |
*---------------*---------------*
| | |
SOD(5) SOD(5) SOD(5)
DGND(4) DGND(4) DGND(4)
| | |
*---------------*---------------*
CGND(6) CGND(6) CGND(6)
| | |
*---------------*---------------*
7) Another method would be to buy SIO sockets, and mount them in a
box, or PC board, and connect them as above. This would allow
you to use unmodified SIO cables.
8) Vendors for the cables and/or connectors:
a) MCM Electronics
650 Congress Park Drive
Dayton, OH 45459-9955
(note: no longer stocks SIO sockets)
b) BEST Electronics
2121 The Alameda Suite 290
San Jose, CA 95126-1127
c) B&C ComputerVisions
2730 Scott Boulevard
Santa Clara, CA 95050
d) American Techna-Vision
15338 Inverness St.
San Leandro, CA 94579
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D) GameLink-II SIO Connections for More Than 3 Nodes:
1) After a fair amount of beta testing and some head scratching, we
discovered that an unmodified Atari's POKEY IC lacks the current
sinking capability to provide reliable operation when more than
3 8-bit computers are linked as described above.
2) An active device (integrated circuit) must be added to provide
the necessary current sinking capability. Rather than include
some complicated instructions, we plan to offer the following
devices for sale to registered owners:
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GameLink-II Docs
a) The OCTO-LINK, which consists of a circuit board,
populated with the required integrated circuit and two SIO
connectors. Unpopulated sites will exist for the addition of
up to six additional SIO connectors by the user (SIO
connectors available from the vendors listed above). This is
ideal for user groups, where the club can purchase one of
these for regular meetings. Use of regular SIO cables
completes the network.
b) The DUO-LINK two-player expandable serial bus cable. This
consists of a circuit board with the necessary integrated
circuit, and serial cable with two ends. It can link two
players together by itself. By purchasing additional cables,
pairs of players can be added. The cables link at their
middles to other cables with heavy duty Molex pins and
connectors. This arrangement allows 8-bitters to own their
own GameLink-II modules, letting them plug together and play
at any time without investing in the 8-player board.
4) As you can imagine, AGDA is not a large commercial concern.
Previous to February 1, 1994 we will be monitoring our GEnie,
CompuServe, Internet, and U.S. Mail addresses hoping for some
response. After that date we will order the necessary raw
materials to create the first batch of the DUO-LINK and
OCTO-LINK connectors. We will sell them to the registered
shareware customers at a nominal fee to cover all expenses.
Keep in touch!
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