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Initial Connect Speed Issues
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.
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.
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.
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.
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).
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
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
2. DOWNLOAD A PRE-COMPRESSED .ZIP OR .SIT FILE
3. DOWNLOAD A FILE THAT'S AT LEAST 200K
4. DOWNLOAD FROM YOUR LOCAL FTP SERVER OR UNIX
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