Over the past 8 years, we have collect numerous files and tips. Some are still needed in a few systems. We keep them here for your use and reference.
Tip on K56 flex by Zoom, may apply to other modems (two techs reporting)
The following is from Don Hinds - Senior Zoom Tech
NOTE: You cannot buy two off-the-shelf 56k modems and connect 56k
between them. The host site must have a special modem \ connection to
special digital equipment.
*** Even between Rockwell 56K modems you will not see any full 56k
connections because at this time the maximum the phone line can support
is about 53K. You are likely to see speeds in the mid 40s or even 30s
because of fallback due to less than optimum line conditions. Even if
your phone line supports 56K, the other line or the trunk line may not.
And every connect speed may not be the same. You may connect anywhere
from 38k-44k on the same phone line in the same hour. The phone company
does not route every call the same way.***
You are more likely to see higher speed connects on long distance
calls, because the lines are newer and cleaner than many local lines. At
this time many telephone lines will not even support a 'full' v34 33.6k
Connect. Most often you will see V34 Connects.
*If you are having trouble connecting at 56K speeds, try putting
S202=32 in your init string. AT&F&C1&D2S202=32
*If the response seems slow after you connect, try going to 16650 UART
Settings of the Modem, and set Transmit Buffers to the ¼ mark (send
speed at 56k is slower so it doesn’t matter). Set the Receive Buffers to
Max or to the ¾ mark.
If you flash upgraded your 56k modem, delete it from your modem list in
the Control panel and re-boot the computer, then re-install the modem.
Put the new mdmzoom.inf file on a disk in A: and when it gets the list
to pick a modem click ‘have disk’ and pick from the new list.
NOTE: While it is theoretically possible to use a setting of 230K, at
the present time most computers, drivers and so forth are not equipped
to do so. You would not see any appreciable (if any) increase in speed
in any case. 230K assumes maximum speed of 56k connect speed
(impossible) and maximum compression of 4X (very unlikely).
NOTE: 56k modems automatically fallback to slower speeds if the line is
not good for the current speed. Newer versions of 56k code probe the
line more aggressively and may have a lower original connect speed. But
they are less likely to have fallback than earlier code. When lines
improve you will get faster speed with no changes on your part.
NOTE: The internet at times is VERY slow. When traffic increases,
transfers may slow drastically, sometimes to a standstill. The same
often holds true for large services like Compuserve, though they are a
lot better than they used to be.
BTW, there is a website for 56K info and answers. http://www.56k.com (note from starck, I have never found this site even though it is mentioned in this email from Zoom)
To test the quality of your lines on v32bis modems, Type +++ and wait
until you get OK. (do NOT press [Enter]). This puts you in command mode. Then
you can enter AT%L?%Q? and it will give you numbers for signal level &
line quality. You should get 15-30 for %L? preferably 18-25, and for Q?
lower is better. 11 or below is what you should get. You can try
forcing higher speeds to see if quality drops at the higher speed, or
force lower to see if quality goes up. (To go back online enter ATO).
NOTE: some modem work with the AT%L? only.
Sometimes your speeds may go down. If the phone company installs a
Mulitplexer on your lines you are likely to lose speed. They install
Multiplexers so they can put more phone lines on fewer phone wires, and
your speed suffers.
If the characters that appear on the screen after you connect are
ALL illegible, then the following does NOT apply. If Some parts of
words are readable, or you have trouble downloading (CRC errors), then
the following probably is the problem, especially if it is worse at
higher speeds. It may stop altogether at lower speeds. Line noise may
also be the cause of FAX or 56K not connecting (or random spots on
Commonly called line noise, problems with downloading or the
spurious characters or garbage that appear on the screen are
usually from the central office of the phone company. It can make a
big difference whether you call Out or someone calls In. Also there is
a difference between calling different areas (area codes or
exchanges) as different equipment will be involved. Calling the phone
company will rarely do any good, because the problem is not on your
line. It is also much more likely to happen on local connections than
long distance. Older cities are more likely to have problems.
For more information on line noise and possible cures check the
following web pages.
(the following two references have not been found to be live but they are in the email from Zoom)
NOTE: ZOOM cannot and does not endorse or recommend any circuits on those pages. You use them at
your own risk. I provided those Web addresses for informational purposes only.
(The only commercial device I ever tested that claimed to stop noise,
cost more than $45 and did nothing at all).
Don Hinds - Zoom Tech
Ps. My 56K modem would not connect at all
from my home (2.5 blocks from Telco Bldg) until
I made and used one of those ‘filters’.
The following is from a junior tech
Use AT&FS202=32S95=1&C1&D2 as the initialization string.
Here are some other suggestions
This should help you troubleshoot K56 FLEX connect problems....
1 You need to check your modems ROM revision, you may use the ati3 command
in any Communication software to do so. (eg.ComitW/Procomm/HyperTerminal)
You also need to check what version your ISP is using. ROM updates for the
Zoom Internal and External modem is currently posted at...
2 There's a alternative list of K56Flex providers posted on our Website
at http://www.zoomtel.com have you tried connected to any of these
3 Have you been able to connect to any K56Flex service at 33.6+ speeds.?
4 You may also use the modem +MS register (see p.49 in Owners Manual) to
force Protocol and Min/Max speed like so....
REMEMBER!! Init Strings for Internet are inserted under Dial-Up-Nets
"Extra Settings" dialog box.
5 It's usually easier to use HyperTerminal or a Terminal Window under
Dial- Up-Networking to dial your ISP's access number like so...
the advantage is that with S95=44 in your string the modem will report all
speeds and Protocols including Carrier speed.
Dial-Up-Net may report Connect (DTE) speed which is a software
compression setting, much more important is Carrier (DCE) speed, you may
try the following...
1 Include S95=44 and/or W1 in your string under "Extra Settings'.
2 Use a "Terminal Windows" to dial under Dial-Up-Networking.
3 Under DUN check "Record to Logfile" and see contents of modemlog.txt
Zoom Technical Support
PS: Please try the above BEFORE attempting a ROM update, I also need the
modem ati3 command response and your ISP's Access Number. This could be a
USRobotics Setup String
This tip comes from DELL computer for the factory installed USRobotics win modems.
"USRobotics recommends the following setup string for their "WinModem" (sportster series).
AT&F1&K0&I0 S33=32 S15=128 S27=64. Those are zero's not o's."
REMEMBER!! Init Strings for modems are inserted under Dial-Up-Nets
"Extra Settings" dialog box.
Test Your Phone Line
USRobotics has a phone line to test your modem against. It was designed for their modems against their modems but, why not try it. 1-888-877-9248, user name is Line Test. You'll get information that you never thought you needed and then some!
Practical 56K Flex recommendations
Init Strings for Common Applications
Many software applications that use your modem must have
an init string. An init string is what tells your modem
how to act. Every software application will require
certain things of your modem. The init string is what
tells your modem to act in a certain manner. For most
applications, your software application will have a modem
pick list. In those cases, you can select your specific
modem from the list. If your modem is not listed, then
you can select on that is most compatible to your modem.
If you have an internal modem but your software only
lists the external version, you can select that as your
modem choice. The internal modems and the external
modems should use the same init string. If your software
does not list any choice that works with your modem,
you can also try using Hayes Compatible setting.
software does not have a modem pick list, in most cases
you can use the default init string of AT&F&C1&D2. That
resets your modem to factory settings and configures it
for optimum usage under most circumstances.
still does not work, you would want to contact the
software manufacturer for the requirements of their
application. They would be able to tell you what their
software requires from the modem. Knowing these
requirements, we can then assist you with tailoring your
init string to fit your software's requirements.
THe following is a listing of init strings for some of
the most commonly used applications.
SOFTWARE PACKAGE INITIALIZATION STRING
America Online AT&F&C1&D2&K3&Q5E1V1Q0X4^M
COMIT for Windows AT&F&C1&D2S95=44
Fax STF for theMac AT&F&C1&D0&K4E0S11=55
PC Anywhere AT&F&C1&D2E0S95=42S0=0W1
Procomm Plus AT&F&C1&D2
QModem Pro for DOS AT&F&C1&D2^M
QModem Pro for Windows AT&F&C1&D2^M
Quick Link II Fax AT&F&C1&D2S0=0
Telix for DOS AT&F&C1&D2S0=0^M
Telix for Windows AT&F&C1&D2S0=0^M
Telemate for DOS AT&F&C1&D2S0=0^M
WinFax Pro 4.0 Class 1 - AT&F&C1&D2S7=90\
Class 2 - AT&F&C1&D2S7=90&K4\