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SMC Barricade and External Modem Hookup
RLSutton Jul-12-01 11:18 AM
This will take a bit of explaining, so bear with me...

When we were looking at DSL for our home a few months back, I purchased a SMC Barricade 7004BR and hooked our two computers to it (both running Win98) and our printer - no problems at all. After over five months and many phone calls to our local TelCo (Verizon), we were told that DSL was not possible due to a multiplexer present in our line (Verizon could not switch our line out of the multiplexer). So much for DSL. Cable Modem is possible but decided against it due to no dial-up backup (cable co. is trying to work that out at present). So that left us with dialup.

I purchased a Zoom DualMode External FaxModem (Model 2949L) and tried to get it running. The Barricade has the latest firmware upgrade and the Primary Setup screen is set for DialUp. The tech support people at Zoom gave me the following initialization string to enter for the modem:


The modem will give an audible click when trying to dial out but no dial tone. If I get a dial tone elsewhere in the house, the modem will dial out and try to establish a connection but can't. Since this is at home, there's no number that you have to dial first before getting an outside line.

I do have messages in with SMC and Zoom but haven't received any responses. Any tips or assistance that you can suggest would be appreciated.

1. RE: SMC Barricade and External Modem Hookup
lbyard Jul-12-01 04:43 PM
In response to message 0
I would work on one problem at a time and get the MODEM working connected directly to a PC first. Larry

2. RE: SMC Barricade and External Modem Hookup
RLSutton Jul-13-01 11:15 AM
In response to message 1
Acutally, the modem does work when I have it hooked up to COM3 (internal modem takes up COM 2 and a serial port mouse on COM1). But not in the way you would expect...

The first time that I tried using the external to dialup my ISP (CompuServe), I got an audible click but no dial tone. The CompuServe software help suggested that I add X3 as an Extra Setting (through Modems on the Control Panel). Second attempt resulted in the same. But when I switched on my cordless phone, got a dial tone and tried the modem again, I heard a dial tone from the modem, the ISP being dialed and got a connection (albeit at 24Kb). Removing the X3 as an Extra Setting resulted in not being able to connect again. Hooking up the phone line to the internal modem again, I was able to get online as one would normally expect.

The modem does work. Getting it to recognize a dial tone on its own seems to be step #1 from here...

3. RE: SMC Barricade and External Modem Hookup
lbyard Jul-13-01 04:01 PM
In response to message 2

The immediate problem could be caused by the Zoom MODEM, serial port, MODEM cable, telephone line, COMPUSERV, or the configuration of the MODEM/port (see FAQ below for troubleshooting). Try the external MODEM on another ISP or BBS (or are they a thing of the past now). You can try it on another ISP without signing-up if you know the phone number. Many ISPs list dial-up numbers on their web sites (many donít, but you must have a friend who doesnít use COMPUSERV). In fact, just about any phone number can be used to test the ability of the MODEM to pick-up the line, detect a dial tone, and dial. Use the Windows Hypterminal, which you will probably have to install with Add/Remove programs in the Control Panel. The MODEM should connect 9ta an ISP), handshake, and you should receive a prompt to login. If that works, try the same thing on COMPUSERV. If you have a phone system other than a regular old phone with a direct connection to phone line, that is probably the problem. The internal MODEM may be causing a resource conflict problem with the serial port used for the Zoom MODEM, try pulling it. Try disabling COM1: on the motherboard if you do not need it for a serial mouse. I stopped using COMPUSERVE many years agoÖ Too expensive, but I suppose you have one of those multi-year contracts that are sold with computers? Larry

Q. How can I test the serial port and cable connected to an external MODEM?

A. There may be a diagnostic program that came with the MODEM, if that is what you are connecting to. A MODEM that uses the Hay's AT command set (most do) can be tested by simply echoing an AT command at the DOS prompt and redirecting it to the COM port, e.g.,


Should cause a MODEM on COM1: to pickup the phone line and you should hear dial tone from the MODEM.


...should cause it to hang-up, killing the dial tone.

MODEM Doctor is a useful MODEM diagnostic shareware program that will check both ports and MODEMs.

Windows 9x/Me has a MODEM Diagnostic at Start, Settings Control Panel, Modems, Select the MODEM, Diagnostics tab, select the port/MODEM, More Info. In Windows 2000: Start, Settings, Control Panel, Modems tab, Properties, Diagnostics, Query Modem.

MODEMs can be tested by dialing a local Internet Service Provider with Windows Hyperterminal (I used to dial a local bulletin board). You can pretty much tell whether the serial port and cable are working or not by typing something in the Windows HyperTerminal and looking at the LEDs on the MODEM. AT commands can be issued from HyperTerminal as well. The MODEM should respond to AT with OK. ATIn should displays the MODEM's manufacturer information for n = 1 through 7. This provides information such as the port speed, the result of a checksum test, and the model information. Check the manufacturer's documentation for the expected results.

MS Diagnostics (MSD) that comes with Windows 95 and MS-DOS 6.X is useful for determining if a serial port is responding (it is also on the Windows 98, 98 Second Edition, and Windows Millennium Edition CD's at D:\tools\oldmsdos where D: is your CD-ROM drive letter).

A loopback test, which requires a loopback plug/adapter, is a very good test of a serial port. Several commercial diagnostics programs (e.g., AMIDiag) come with a loopback plug. When a loopback test is run data is sent out the serial portís transmit pin to the loopback plug which sends the data back to the portís receive pin. This test assures the 1488 and 1489 buffer chips or equivalent are working and they are the chips that are usually damaged by a close lightning strike, etc. Scott Muellerís Upgrading and Repairing PCs has more info and instructions for making a loopback plug. Just search Google for the book. Every shop should have a copy. However, the best and easiest to read shop reference on serial ports and cables I know of is Data Communications for Microcomputers by Elizabeth A. Nichols, Joseph C. Nichols, and one of my business acquaintances from the old days, Keith R. Musson, McGraw-Hill 1982. I think it is out of print.

An RS-232 breakout box and a multimeter are useful tools for troubleshooting serial ports and cables.

4. RE: SMC Barricade and External Modem Hookup
RLSutton Jul-16-01 01:02 PM
In response to message 3
Larry - thanks for the advice. But after talking with one of the Zoom Tech Support people on my cell phone while running tests on the modem, it appears that the modem is not functioning correctly even though the diagnostics on the modem seemed to be fine. I am following Zoom's suggestion and returning the modem for a replacement. Once I get the replacement in, I'll make sure it works hooked up to a computer first before transferring it over to the SMC unit.

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