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== Review: GVP ioExtender By: William Near ==
HARDWARE: GVP ioExtender
MANUFACTURER: Great Valley Products Inc.
657 Clark Ave.
King of Prussia, PA 19406
(215) 354-9495 (automated voice)
(215) 337-9922 (fax)
(215) 337-5815 (BBS)
72662,51 (Email on CompuServe)
DESCRIPTION: High speed serial and parallel expansion for A2000/3000/4000
PURCHASED FROM: Software Hut
313 Henderson Drive
Sharon Hill, PA 19079
(800) 93-AMIGA - orders
(610) 586-5701 - info
(610) 586-5706 - fax
PRICE: I paid $115 U.S. this includes $6 S&H
SYSTEM REQUIREMENTS: Amiga 2000/3000/4000 running Workbench 1.3+
SYSTEM TESTED ON: Amiga 2000 (Rev 4.4),
ECS chip set,
GForce '030 accelerator @ 50 MHz.,
2 megs CHIP + 6 megs FAST memory,
2 standard floppy drives,
Quantum LPS270S hard drive with Trumpcard Professional
Epson LQ-510 printer
DSS 8+ audio digitizer
PACKAGING: The foam lined box contained the ioExtender board wrapped in a
static resistant bag, one floppy disk of software, and a manual with
registration card attached.
INSTALLATION: You must first configure the ioExtender board for the proper
configuration before installing it in the computer. The parallel port on
the ioExtender can be set, by use of a jumper, to behave as either an Amiga
(with 5 volts supplied on Pin 14) or an IBM (with no power supplied)
standard parallel port. Make sure that this jumper is set correctly as you
can damage peripherals connected to the parallel port that are not
expecting the voltage sent through the cable. The ioExtender board's
serial port may be set, by use of two jumpers, to act as a Null Modem port
(this just switches the Transmit Data (TXD) and the Receive Data (RXD)
lines. If you have purchased the optional second RS-232 serial port (I
didn't), connect its ribbon cable to the 10-pin header at the top of the
board (you must also set one jumper to tell the ioExtender that an
additional port is present.) Once the ioExtender board is configured
correctly, it easily installs in any empty Zorro slot in the computer. If
you have the optional serial port attached you can just install it in an
adjacent, empty Zorro slot.
Now you can attach your printer and/or modem cables to the ports on the
ioExtender. The board's parallel port is a standard DB-25 port while the
serial port is a DB-9 configuration. I only had a DB-25 to DB-25 cable for
my modem, so I had to purchase a DB-9 to DB-25 cable in order to connect my
modem to the serial port.
The software contained on the floppy disk uses the Commodore Installer
program which makes it a breeze to place the files on your hard drive. The
ioExtender's files consist of: SetDevice (placed in the C directory), GVPio
(placed in the Expansion directory), GVPPortHandler (placed in the L
directory), GVPioControl and GVPSerial (both placed in the Prefs
directory), and finally one line is added to your User-Startup script.
SOFTWARE CONFIGURATION: There are three ways to make your software use the
ioExtender's ports. The first, and best way, is to make your
communications software directly address the board's serial port by
replacing the serial.device with gvpser.device in the configuration area.
I did this with GPFax v2.342 and TERM v4.1a and it works flawlessly in both
The second method involves the use of two logical devices: GVPpar0: and
GVPser0:. Some programs will allow you to specify a logical device as an
output device and this is also the preferred method when programming in
ARexx (according to the manual.)
The third method involves the intercepting of all calls to the Amiga's
parallel and serial ports and redirecting them to the ioExtender ports via
the GVPioControl software.
GVPioControl: This is the GUI that controls the redirection of serial
and parallel port calls by setting conditions for the SetDevice program.
SetDevice is run each time your computer is turned on and it monitors the
Amiga's serial and parallel port activity.
The GUI presents you with a series of rollover gadgets: Serial Port, Unit,
Mode, Parallel Port, and Unit. Also included are: Save, Use, and Cancel
Serial Port - you may select either the Amiga's internal serial port or the
ioExtender's serial port as the default.
Unit - you may select a unit number for the serial port in the range of
0-11. This makes it possible to control up to 12 optional serial ports on
your Amiga in addition to the one internal port.
Mode - this option allows you to select one of the following for each unit
number: RS-232, MIDI, or AUX. The RS-232 setting is the standard option
which makes use of the DB-9 serial port on the board. The AUX setting uses
a 34-pin Option header which is reserved for future use. The MIDI option
has a predefined setting for connecting MIDI devices to the ioExtender.
Parallel Port - you may select either the Amiga's internal parallel port or
the ioExtender's parallel port as the default.
Unit - you may select a unit number for the parallel port in the range of
0-5. This makes it possible to control up to 6 optional parallel ports on
your Amiga in addition to the one internal port.
Save - this button is used to permanently save the new settings and exit
the GVPioControl program.
Use - this button will use the current settings and exit the GVPioControl
program, but it will not save the settings permanently.
Cancel - this button will exit the GVPioControl program and any changes
made will not be saved or used.
GVPSerial Preferences: This is the GUI that allows you to control the
ioExtender's serial port(s). The GUI presents you with the following
options: Baud Rate, Input Buffer Size, Handshaking, Parity, Bits/Char, Stop
Bits, and Unit Number. Also included are: Save, Use, and Cancel buttons.
Baud Rate - the serial port on the ioExtender is capable of baud rates up
to 115,200 bps. The range of slider settings is from 110 to 115,200 bps.
The slider also has three settings that appear past the 115,200 setting,
they are: MIDI, CUSTOM, and MAXIMUM.
MIDI - this setting is used when a MIDI device is attached to the
ioExtender's serial port. The typical MIDI setting is 31,250 bps.
CUSTOM - this setting is used when you wish to enter a custom
transmission rate. When you use this setting you must access the
Miscellaneous pulldown menu and select the Set Custom Baud Rate menu item.
A requestor will appear with a text field that may be used to enter your
own custom rate. If you enter a value that the ioExtender is incapable of
delivering, you will see a display showing the actual baud rate achieved
and the percentage of variance from the entered rate.
MAXIMUM - this setting will drive the ioExtender's serial port as fast
as it can.
Input Buffer Size - the serial port on the ioExtender has a 16 byte
hardware buffer for receiving and transmitting data. This slider lets you
adjust the software buffer to be used as a cache for incoming data while
your program is doing other tasks. The slider has a range of 512 to 65,536
bytes. According to the manual, a 2 meg Amiga system can easily support a
16k serial buffer.
Handshaking - this radio button selection offers: XON/XOFF, RTS/CTS and
Parity - this radio button selection offers: NONE, EVEN, ODD, MARK, and
SPACE parity bits.
Bits/Char - this radio button selection offers: 5, 6, 7, or 8 Bits per
Stop Bits - this radio button selection offers 1 or 2 Stop Bit settings.
Unit Number - this gadget allows you to select which serial port you are
controlling by using the + and - buttons to select one of the twelve (range
of 0-11) possible choices. As you cycle through the possible choices a
text line located below the selector will show the identity and location of
the selected port.
The GVPSerial Preferences program also contains three pulldown menus:
Project, Edit, and Miscellaneous.
Project - this menu contains an Open choice for loading a predefined
settings file, a Save As menu choice for saving a settings file that does
not become the default settings file for the GVPSerial Preferences program,
and a Quit menu choice for exiting the program from the pulldown menu
instead of from the close gadget.
Edit - this menu contains a Reset to Defaults choice for resetting the
preferences icon to the factory defaults, a Last Saved menu choice for
restoring the user-defined settings as contained in the preferences icon,
and a Restore menu choice for resetting the selected unit to its settings
which were in effect before the most recent changes were made.
Miscellaneous - this menu contains the Set Custom Baud Rate choice as
described in the Baud Rate/CUSTOM section earlier in this review.
The GVPSerial Preferences GUI also contains the Save, Use, and Cancel
buttons which serve the same function as their counterparts in the
GVPioControl program described earlier in this review.
OTHER STUFF: The manual has a section that describes various modem and
printer setups. According to the manual you could have five separate
ioExtenders with their optional serial ports attached, thus giving you the
capability to attach ten modems to your Amiga and a BBS package.
Also, if you are using GVP's DSS 8 audio digitizer, you can attach it to
the Amiga's internal parallel port and it will function properly since it
bypasses the system-level operations and accesses the circuitry directly.
I have a DSS 8+ audio digitizer and I have used it simultaneously with my
printer attached to the ioExtender's parallel port, both work flawlessly!
At the end of the manual there is a trouble shooting section which
describes many common problems with setting up and using the ioExtender's
hardware and software.
SUMMARY: The ioExtender is an invaluable addition to your Amiga if you have
the need for additional high-speed serial and parallel ports. It's really
nice to have my modem, printer, and audio digitizer all connected at the
same time. No more turning the computer on and off to connect the printer
or audio digitizer to the Amiga's internal parallel port. Also, I can now
play a MOD, print a file, and upload or download files at 14.4k without ANY
I had originally purchased a MultiFaceCard III to serve the same purpose.
I found that card's parallel port to be incompatible with Workbench 3.1 on
the A2000 and you could not access the Amiga's internal parallel and serial
ports when the MFC III was active. I had to create two icons using ICONX,
one to redirect the output to the Amiga's internal ports and the other to
redirect output to the MFC III's ports. This arrangement was very clumsy
and since the MFC III's parallel port didn't work under WB 3.1, I couldn't
attach my printer and audio digitizer at the same time. This effectively
nullified any reasons for buying the MFC III in the first place! For my
purposes, even though the GVP ioExtender was approximately $30 more it was
the better buy as compared to the MFC III.