Initial Connect Speed Issues
Help! My 56K modem connects at 33.6 or less!
Even if I don't connect at 56K, I'm guaranteed
33.6, right?
I'm connecting at 38400, 57600, or 115200. Or am I?
How can I get my modem to report the true connect
speed?
What are typical connect speeds for 56K modems?
Is initial connect speed all it's cracked up to
be?
What's the command for connection speed and stats
on my K56flex?
What's the command for connection speed and stats
on my USR?
What's a good way to test actual modem performance?
(FTP)
Help! My 56K modem connects at 33.6 or less!
Treat this as a troubleshooting matrix. Go through all of these steps,
and you will have a better than 90% chance of solving your problems with
slow connects.
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THE OBVIOUS STUFF
We hate to ask, but you did check the obvious things, right?
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- Make sure that you and your Internet service provider use the same
56K protocols. 56K requires that both ends have 56K modems, and they
both have to use the same kind of 56K technology (x2, K56flex, or
V.90). Despite what you may have heard, V.90 is not the same as x2 or
K56flex. It is a third and distinct 56K protocol. Your ISP will be
able to tell you which protocol they use.
- Some Internet service providers have separate phone numbers for 56K.
Make sure you're calling the right number.
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THE EASY ANSWERS
Things that are easy to try even if you don't know much
about computers. Don't skip this section, because these fixes
often work.
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- If there is a telephone, answering machine, etc., plugged into the
back of the modem, unplug it from the back of the modem. The modem is
supposed to ignore devices plugged into it when it is online, but that
is not always the case.
- Try disconnecting additional telephony devices (fax, phones,
answering machines, alarm systems, etc.) from the phone line, even
if they're in a different room. I've heard from readers whose
connect speed jumped 10K when they unplugged a fax machine or cordless
phone in another room.
- Also try running the phone line directly from the back of the modem
to the wall, without passing through surge suppressors, splitters,
phone line extenders, etc. This is a basic and useful step in modem
troubleshooting.
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MODERATELY DIFFICULT ANSWERS
These require slightly more computer skill. If you don't
know how to use a terminal program, click on the links for help.
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- DO NOT SKIP THIS NEXT STEP. It's always a good idea to check the firmware
page to see if there is a more recent firmware version available.
Many people's problems have disappeared once they installed a new
version of the firmware.
- Visit the inits and drivers page
to see if there is an init string or better yet a driver for your
modem. If there is, download and install it. The inits and drivers
page includes installation instructions.
- If your modem supports more than one 56K protocol, you may want to
tell it which protocol (V.90, x2, or K56flex) it should use. The
commands are listed on the interoperability
page.
- It's possible there is an incompatibility between your modem and
your ISP's modems. You might try dialing into some other local ISPs.
You don't have to join or do anything after you connect: just see how
fast you can connect to their modems.
- If this is a Rockwell-based K56flex modem, issue an ATI3 command in
a terminal program. If the
version number includes the letters "DSP", click
here. If the version is 0.5 something, and your Internet service
provider uses K56flex Livingston Portmasters, click
here. If the version is 1.0 something, you should try adding
S202=32 to your init string.
- If this is a Lucent-based K56flex modem, issue an ATI3 command in a terminal
program. The firmware version should be at least 4.06, and higher
versions are better. Click
here for more information.
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OR MAYBE IT'S YOUR PHONE LINE
I was hoping it wouldn't come to this, but it may not be
your modem or inside phone lines at all.
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It may be that the phone lines in your immediate neighborhood don't
support 56K
As explained in the Basics section of the 56K Primer, multiple
digital/analog conversions will prevent the use of 56K technology and
limit your modem to V.34 speeds (a maximum of 33.6K).
"It's not my phone lines. I know they support 56K"
OK, how do you know your phone lines support 56K? 3Com's
line test is not guaranteed. It can tell you that your phone line
supports 56K when in fact it doesn't, and vice versa. Don't put all of
your faith in it. If you must use the test line, 3Com recommends calling
it multiple times (ten times, say). On some calls it may say your line
supports 56K and on other calls it may say the opposite.
The fact that your modem can connect at 56K speeds to a long distance
number is no guarantee that the same is true of local numbers, and vice
versa. Long distance calls may be routed through telephone circuits which
are significantly better or significantly worse than the local circuits
used to connect to your ISP.
How to find out for sure if your phone lines support 56K
This is the only reliable way I know of to test your phone lines:
borrow a known good 56K modem and try it with your phone lines. By
"known good 56K modem," I mean a modem that has connected at
speeds higher than 33.6. Remember that connects speeds of 38400, 57600,
and 115200 aren't true connect speeds, so they don't count.
If it's an internal modem, have your friend bring the whole computer to
your house. In fact, it's easier that way, because his computer will
already be configured for his modem. Let him use your monitor, keyboard,
and mouse so he won't have to cart them over to your house.
If you can only borrow the modem, be sure to get the disks that came
with the modem so you can install the drivers for that modem. You'll have
to install the modem and drivers. Be sure to select the modem in your
dialing software (such as Windows 95 Dial-Up Networking or Apple's PPP for
Open Transport). Instructions are on the Inits
and Drivers page.
Once his modem is at your house, call his ISP. How fast is the
connection? You can also try calling your ISP, if your ISP and your
friend's modem use the same 56K protocol (x2, K56flex, or V.90).
More about multiple digital/analog conversions, and what to do about
them
Office PBX systems generally create an extra A/D conversion. How do you
know if you're on a PBX? If you have to dial a number (usually 9 in the
U.S.) to dial an outside line, you're on a PBX. If your phone has its own
extension, you're on a PBX. The solution in that case is to plug the modem
into a direct outside line. The office fax machine is usually dialed into
a direct outside line, so try that.
The phone lines outside of your building may have equipment that
introduces extra A/D conversions. Non-integrated SLCs (subscriber line
concentrators) are one source. If that's the case, there's little you can
do except to call the phone company and complain. Before you get your
hopes up, be aware that the phone company is generally not sympathetic,
and only guarantees speeds of 9600 baud or so (the exact answer will vary
from telco to telco). It is worth a shot, though, and some people have
managed to get their phone company to re-route the lines.
Even if I don't connect at 56K, I'm guaranteed
33.6, right?
No. In fact, even if you and your ISP were using 33.6 modems, you still
wouldn't be guaranteed 33.6 connects. Few people get 33.6 connects. A
large number get 28800 or 31200 connects, but many people only connect at
26400, 24000, or even slower. The phone lines in some areas simply can't
support higher speeds.
If you'd like to try improving the speed, make sure you have the latest
firmware and drivers/settings
files. Also, try passing the phone line directly from the back of the
modem to the phone outlet on the wall. Passing the phone line through
surge protectors, phones, answering machines, etc., has sometimes been
responsible for slow connects.
Again, though, your phone lines may simply not support higher speeds.
I'm connecting at 38400, 57600, or 115200. Or am I?
No. Those speeds are computer-to-modem speeds (AKA DTE speeds or port
speeds) that you set in your software. What you want to know is the
modem-to-modem speed (AKA connect speed or DCE speed).
Your <-DTE Speed-> Your <-DCE Speed-> Remote
Computer Modem Modem
How can I get my modem to report the true connect speed?
For Windows 95 Dial-Up Networking and Apple's PPP for Open Transport
You must install the correct drivers for your modem. For instance, you
would need to the correct .inf file for Windows 95 Dial-Up Networking, or
the correct CCL file for Apple's PPP for Open Transport. The drivers
interpret the result code from the connection and translate it into a
connect speed. Without the driver, you won't get an accurate connect
speed. These may have been included on a disk with the modem. If not,
check the 56K.COM Inits and Drivers
page, which has links to downloadable drivers and instructions for
installing the drivers.
If you have the correct driver/settings file and you still don't get
the true connect speed, add one of the init strings below to your init
string.
For other programs that do not use driver files
According to 3Com/U.S. Robotics, any init string that includes
AT&F1 should report the true connect speed.
For most Rockwell-based 28.8 and K56flex units, the command is W2. (For
Rockwell-based PCI modems, the command is MR=2.) However, several commands
can override W2, including the S95 commands and the &Q commands. If W2
doesn't have the desired effect, you might try adding S95=0 or S95=1 to
the init string.
What are typical connect speeds for 56K modems?
As with 33.6 modems, your results will depend heavily on your phone
lines. To see what kind of performance other people are getting, see the performance
survey. Typically, 42-46K for K56flex and anywhere from 44-52K for x2
is good performance. Some people are getting better results, some are
getting worse.
Is initial connect speed all it's cracked up to be?
Initial connect speed is a convenient benchmark, but it can be
deceiving. V.34 and 56K modems can and do shift their speeds up and down
during the course of the call to respond to changing line conditions. Some
modems connect very aggressively at high speeds, but are then forced to
lower their speed to a more stable level. Others may connect
conservatively and upshift.
The best test is to download a compressed file with FTP. For help with
getting accurate results, see the section below on FTP.
What's the command for connection speed and stats on my K56flex?
Lucent-based K56flex modems
After disconnecting, issue an ATI11 command in your terminal
program.
Rockwell-based K56flex modems
After disconnecting, issue an AT&V1 command in your terminal
program. These are some example results. TX is the transmit (upload)
speed. RX is the receive (download) speed.
AT&V1
TERMINATION REASON.......... LOCAL REQUEST
LAST TX data rate........... 31200 BPS
HIGHEST TX data rate........ 31200 BPS
LAST RX data rate........... 46000 BPS
HIGHEST RX data rate........ 50000 BPS
Error correction PROTOCOL... LAPM
Data COMPRESSION............ V42Bis
Line QUALITY................ 127
Receive LEVEL............... 014
Highest SPX Receive State... 00
Highest SPX Transmit State.. 00
EQM Sum Value............... 00A2
RBS Pattern detected........ 00
Data Rate Dropped in kbps... 00
Digital Pad Detected........ None
What's the command for connection speed and stats on my USR?
After disconnecting, issue an ATI6 and ATI11 in your terminal
program. These are some example results. Note that the ATI6 Speed line
shows the highest download/upload connect speeds. The ATI11 command shows
the number of upshifts and downshifts for receive (RX) and send (TX).
ATI6:
Chars sent 580 Chars Received 49642
Chars lost 0
Octets sent 360 Octets Received 26533
Blocks sent 191 Blocks Received 805
Blocks resent 0
Retrains Requested 0 Retrains Granted 0
Line Reversals 0 Blers 1
Link Timeouts 0 Link Naks 0
Data Compression V42BIS 2048/32
Equalization Long
Fallback Enabled
Protocol LAPM SREJ 128/15
Speed 46666/31200
Last Call 00:04:34
Disconnect Reason is Escape code
ATI11:
USRobotics Courier V.Everything Link Diagnostics...
Modulation x2/V.34+
Carrier Freq ( Hz ) NONE/1920
Symbol Rate 8000/3200
Trellis Code NONE/64S-4D
Nonlinear Encoding NONE/ON
Precoding NONE/OFF
Shaping OFF/ON
Preemphasis Index NONE/0
Recv/Xmit Level (-dBm) 15.7/12.2
SNR ( dB ) 61.5
Near Echo Loss ( dB ) 10.2
Far Echo Loss ( dB )
Roundtrip Delay (msec) 26
Timing Offset ( ppm) -1406
Carrier Offset ( ppm) 68
RX Upshifts 0
RX Downshifts 1
TX Speedshifts 0
x2 Status 0000; 0000-0000-0001-0000-0000-0000; 00,00 0031;03
What's a good way to test actual modem performance? (FTP downloads)
If done correctly, file downloads are a good way to test modem
performance. The trick is to make sure you're really testing the modem's
raw transfer rate, and not some other factor that you're not aware of.
Here are some guidelines for download testing:
1. USE AN FTP PROGRAM
Web browsers often lie about download rates. FTP is more reliable. Note
that some FTP programs reports download speeds in Kilobits per second
(Kbps), while others use Kilobytes per second (KBps). To convert, multiply
Kilobytes per second by 10 (eight bits plus the start bit and stop bit).
(V.42 error correction strips out the start bit and stop bit, but adds
other overhead, so multiplying by nine may be more accurate.) A valid
alternative to FTP is a terminal program that supports Zmodem.
2. DOWNLOAD A PRE-COMPRESSED .ZIP OR .SIT FILE
If the file you download isn't compressed, hardware data compression in
the modem will kick in, leading to erroneous results. Different file types
compress to different degrees, so if you download a Microsoft Word file
and I download a QuickTime movie, there's no way to compare the results.
Use .zip (PKZip/WinZip) or .sit (StuffIt) files for your tests. Some file
formats (GIF, JPEG, QuickTime, etc.) offer some compression, but can
sometimes be compressed further by hardware protocols.
3. DOWNLOAD A FILE THAT'S AT LEAST 200K
A file size of at least 200K will minimize the effects of TCP/IP slow
start.
4. DOWNLOAD FROM YOUR LOCAL FTP SERVER OR UNIX DIRECTORY
A local server is one that's on your system, not on the other side of the
Internet. If you download a file from across the Internet, you're testing
your ISP's connectivity to the Internet just as much as you're testing
your modem.
Most ISPs have FTP sites at ftp.ispname.com. If you're on AOL, for
instance, go to ftp.aol.com to download files. There will usually be a
directory called pub that contains downloadable files.
5. DOWNLOAD DURING OFF HOURS
To eliminate congestion issues, download early in the morning or late at
night.
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