One day I was cruising
eBay when a Griffin gPort jumped out at
me. It was something I was somewhat familiar with, being one of those
things I had thought of buying around the same time I bought my
computer, but I never got around to.
The Griffin gPort is a device that adds a standard Macintosh serial
port (RS-422) to the Blue
G3. While many 
manufacturers made PCI cards to
do this, Griffin opted to use the internal modem slot instead. The only
downside is that the test computer slowed down significantly while
printing. This didn't happen when using either a hardware bridge or a
Mac IIci connected to the G3 via
ethernet and the printer by LocalTalk. However, it's not unusual at all
for a machine being used as a LocalTalk bridge to slow down
significantly while the document spools across the interfaces.
One of the major issues with the earlier serial port PCI cards was
that they did not support LocalTalk, so while you could use it to
attach an older serial device or printer, it couldn't be used to
connect to a LocalTalk network. For many people this wasn't a major
issue, but as I work with a lot of older Macs, I like to have a way to
transfer information easily between my computers.
The other problem with using PCI solutions is the small number of
PCI slots. Macs have always been a little PCI-slot hungry, and the Blue
G3 is no exception. For many people that fill their PCI slots with SCSI
cards, multiple display cards, or professional sound cards, there just
isn't enough room. The downside, obviously, is that you cannot have an
internal modem. As I bought my Blue G3 without the modem, this wasn't a
problem, but it will definitely be a consideration for some people.
I managed to get my gPort at about half the retail price on eBay. It
unexpectedly turned out to be the "Professional" version, which
included a nice cute three-port MiniDIN-8 switch. The gPort retails for
around $50 for the standard edition, with the Professional Edition
selling for an additional $10. The only difference between the standard
and professional models is the three-port switch, which may or may not
be of use to you. The switch is very small, which is both good and bad.
Despite the length of the cable, it is sometimes hard to reach the
switch. My Blue G3, Chtzrik, sits under my desk, and this makes it
impossible to reach the switch. As I use a standard size 2-port
MiniDIN-8 switch anyway, I just daisy chain Griffin's into my old
clunky one. To this day I've never had all five ports filled at the
same time, but I have come close.
Installation was remarkably easy, partially thanks to the decent
manual that was included. By decent I mean by today's standards - it
still wouldn't have been enough to make a double period's worth of spit
balls in high school (estimation only). In any case, it was useful.
There were only three parts to the hardware - a board that fit into
a slot on the logic board, a board that screwed onto the back of the
case with the port, and a cable to join the two. It was somewhat
reminiscent of installing an ethernet card into an SE, only much easier. (If you manage
to break a CRT installing a Griffin gPort you may have done something
wrong.) After closing up the case, I installed the included software.
It is available for free download from their website, which was what I
did. Being on a college LAN with a backbone Internet connection, I tend
to download drivers to ensure I get the latest version. In this case,
the version I downloaded was the same as the version included in the
box. If I thought installing the hardware was easy, installing the
software was almost a joke. Four or five mouse clicks (and a license
agreement) later, the computer restarted and my gPort was ready to try
out.
The first thing I did was to try to establish a LocalTalk connection
with my pet Macintosh IIci that
perpetually occupies a few precious square feet on my desk. Initially I
set up the IIci as the file server and went into the Chtzrik's
AppleTalk control panel. A new option greeted me: Modem Port. Makes
sense - it uses modem slot, has a little telephone icon next to the
port, and has the same plug as a traditional Macintosh modem port. I
closed that window (yes, I would like to save my changes), opened the
Chooser, and my IIci showed up in the AppleTalk window. The second test
was with a printer - my Mom's Hewlett-Packard 855c. After downloading
and installing the drivers, I once again opened the Chooser. Under the
"DJ 800 series" header was an icon identical to the modem/printer port
of many PowerBooks. In another printer driver it was called the
Printer/Modem Port. Printing worked great, no difficulties beyond any
that one would experience on a beige Power Mac.
The next concern was speed. I had no reason to suspect that the port
would be any slower than the high-speed serial of older, beiger Macs
(230.4 kbps). However, as the modem only needs 56 kbps throughput, the
slot might not have been capable of providing as much bandwidth.
Conversely, it might have been capable of far higher speeds.
In order to get an idea of its speed, I transferred a small file
between Chtzrik and my IIci, timing it with a watch. This was slightly
faster than the same transfer between Mom's 7100 and the IIci, which I
attribute to three times the RAM and the Ultra2Wide hard disk. I really
would like to get a proper benchmarking utility to test this with
(please email suggestions - Norton's doesn't count). Miscellaneous file
transfers between Chtzrik and a 6400 seemed no faster than between the
7100 and the 6400. All this satisfies is that the gPort is capable of
maintaining the same throughput as older machines.
I would be interested to clock the speed between two gPort-enabled
Blue G3s to see if it is capable of speeds higher than the standard
Macintosh serial port. It is unlikely that it is significantly faster,
as there would be little practical use to such a design - the only way
the extra speed could be used would be between two Blue G3s, which
already have 100 Mbps Ethernet built in.
As one must sacrifice the internal modem of the Blue G3 in order to
add the Griffin gPort, I explored the possibility of connecting an
external serial modem to the port. I used the Global Village Teleport
Platinum and the Global Village Teleport 33.6k. On both Chtzrik and the
7100, they connected at 28.8 kbps and 31.2 kbps, respectively.
According to the Cnet bandwidth meter, the bandwidth was identical for
both machines on the 33.6 modem, while the 7100 measured as faster on
the Platinum. It wasn't a significant difference, and I'm attributing
that to random Net congestion.
In a real world download of a 600 MB file, the speeds were very
similar, Chtzrik being ahead by about 2% - once again probably due to
the faster disks or the larger amount of RAM.
All in all, the addition of the Griffin gPort to my Blue G3 was the
easiest modification I have made so far. I've had less trouble with the
gPort than I have with additional hard drives, PCI cards, and even RAM.
It has been a very dependable and useful addition to my computer, with
the only disadvantage being the need to use an external modem for
remote access.
One should note, however, that one can't use the gPort for a
LocalTalk bridge. This is because, as Apple states, that LocalTalk
Bridge is only partially compatible with OS 8.6 and not at all
compatible with OS 9. I attempted to run LocalTalk Bridge under
MacOS 9.0.4 with results varying from nothing to a system crash.
As far as I am aware there are not yet drivers for the gPort under
OS X, so that could be a consideration if you plan on using
OS X.
UPDATE: Paul Griffin of Griffin Technology, Inc. emailed me to point
out some software that Griffin had released to allow blue G3s to use
LocalTalk Bridge. In my tests, I was unable to make the gPort work with
LocalTalk bridge. I attributed this to Apple's claims that it is not
fully compatible with Mac OS 8.6 and incompatible with OS 9. After
doing some tests on a beige G3, I found that LocalTalk Bridge 2.1
worked fine under Mac OS 9.1. Griffin's web page notes that the reason
it does not work with Apple's LocalTalk Bridge is because the gPort
reports itself as a modem port, not a printer port (which LocalTalk
Bridge requires). The software from Griffin patches Apple's LocalTalk
Bridge to recognize the modem port for the bridge. So far I have found
it stable and reliable.
As for OS X compatibility, Paul Griffin has the following to say:
"We are working on a OS X driver that would allow some OS 9
applications and drivers to work when run in Classic mode. Any existing
OS X serial drivers should already work. There are not a lot of
these yet, but we have tested modems and they worked fine."
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