Modems

• What are Controllerless Modem and Software Modem?
  In general, a modem system can be divided into three parts:

  Controller: This part communicates with the CPU via the bus (PCI or ISA) interface, executes modem AT command sets, handles data access between applications and datapump, and also executes the error correction and data compression algorithms.

  Data Pump: This part handles floating point operations like FFT, DTMF, and other tone generation and detection, modulation and demodulation and spectrum analysis. This part is the engine of the modem, the kernel of modem operation. It modulates data from the controller and transmits the analog signals to the DAA. It demodulates the received signals from the DAA and sends the data to the controller.

  DAA ( Data Access Arrangement ): DAA (Data Access Arrangement): This part contains analog circuits to provide the characteristics required to connect to the telephone network. The matching characteristics include line impedance, current sink and hybrid circuitry. The DAA also enables features such as Caller ID and pulse dialing.

  Hardware Modem: If a modem contains controller, data pump and data, it is a hardware modem.
  
  Controllerless Modem: As CPU's become more and more powerful, internal modem structure can be saved by moving some parts to the CPU. If we move modem command execution to the CPU, we can skip the controller. This is a controllerless modem.
  
  Software Modem: If we move the tasks of the controller and data pump to the CPU, and just use an ASIC to handle the PC interface, we have a software modem. Software modems do not contain a data pump or controller but will require more CPU resources. In general, a Pentium MMX-200 will be the minimum requirement for a software modem.
• How to identify my modem can support 56k or not?

  There are two ways to help you to determine whether your modem is 33600bps (33.6kbps) or 56000bps (56kbps).
  
  First there is the "OFF LINE" method to determine the speed of your modem. If your modem is installed in your PC you will need to remove it. You can directly view the label of the largest chip on your modem.
  
  you can see like:
  RCVDL56ACFW/SP
  R6772-22
  ROCKWELL 97
  9814 B57736-5
  MEXICO
  
  If you can see the word 56 in the first row, then your modem is a 56kbps modem. If you only see the word 336 in the first row, then your modem is only a 33.6kbps modem.
  
  Second there is the "ON LINE" method to determine the speed of your modem. Your modem needs to be installed in your PC correctly, via the following procedures to know whether it is a 56kbps or 33.6kbps modem.

  1. Click Start, point to settings, and then click Control Panel.
  2. Double-click Modems

  If you can see the number 56, in TAICOM_MR56SVS_56000 or Aopen_FM56_EX_56000 for example, then your modem is a 56kbps modem.

• How do I identify which firmware revision my modem has installed?

  Exit current ISP connection

  1. Go to My Computer --> Control Panel --> Modems --> Diagnostics
  2. Select the COM Port your modem is using
  3. Select "Information" and press it
  4. If the modem is enabled, you will find the ATIX string where “X?in the ATI name denotes ATI3, for example, as the firmware version.

  The other method is to issue AT commands under a communication utility like HyperTerminal from the Accessories menu. In terminal mode, type the commands given below
  ATZ: Reset modem
  AT&F&W : Load the factory default setting and save it to EEPROM.
  ATI3: Get Firmware information
  ATI4: Get Manufacture Company information
  AT+MS?: Get the communication protocol the modem supports (V90 or K56)

• What is the procedure to display real ISP connection speed instead of default 115200 bps?

  115200 bps is the speed between the modem and your computer. You can use the following procedure to display the true connection speed.

  1. Exit current ISP connection
  2. Go to My Computer --> Control Panel --> Modems --> Properties --> Connection --> Advanced --> Extra Settings --> and type in:
     AT+MR=2
     
     --> OK --> OK
  3. Reconnect ISP
• Why my system freeze for a few moments while PCI modem dial out?
  The system freezing shortly is normal, it only last for a few seconds. Perhaps around 0.5sec to 1.5sec. At this moment, the modem occupies most of the CPU resources. It's normal to have this symptom.
• Some tips on configuring communication software.
  Your fax/modem uses the most up-to-date industry and commercially popular standards to ensure functional compatibility with most communication software. During initial set-up of the communication software, it will normally prompt you to define the type of fax/modem you are using. Following is a general guideline to the device type you should choose. NOTE: The device type only defines the protocol by which your software will communicate with your fax/modem and does not set or limit the speed. For modem device type, choose 'Hayes V.32' or 'Hayes Compatible' modem. For the baud rate. choose 115,200 bps.Your fax/modem will automatically adjust to the best transmission speed after successfully connecting with a remote fax/modem. Many communication programs use the modem response to control program flow. There are three flow control modes: none, hardware (CTS/RTS) or software (XON/XOFF). Set your software to use either hardware or software flow control. If set to none, the communication software will not be able to detect a buffer overflow and result in transmission errors. For fax device type, choose 'TR29 Class 1'. For fax speed, choose 'automatic' or 'fastest speed'. Your fax/modem will automatically adjust to the best transmission speed after successfully connecting with a remote fax machine or another fax/modem. Make sure that you have correctly set all the other parameters required by the software to operate successfully. Refer to the manual that came with your communication software for details
• What is V.90 ?

  A modem is a type of communication device. To achieve compatibility, two sides of connection should follow the same communication protocols. In general, the ITU (International Telecommunication Unit) responses to build up the protocol for telecom devices. ITU's last modem protocol is V.34Plus, it supports point to point connection (end-user to end-user) and can provide maximum data speed 33.6K bit per second (bps). To achieve higher data transfer rate in the same twisted wire media, private companies have developed new technology to increase the data speed to maximum 56K bps. There are two groups of companies can provide such technology: Rockwell K56flex and 3Com X2 respectively. Unfortunately, these two protocols are exclusive, so the connection speed will drop to 33.6K bps between X2 and K56flex. To solve this problem, ITU integrates both K56flex and X2 to V.90 protocol. V.90 have the following characteristics:

  1. V.90 can not be used in point to point connection. It only can be used in client - server modem connection. It means ISP should build up server modem and connects the server modem to telecom central office.
  2. V.90 only provides download path ( ISP to end user ) 56K bps , the upload path is limited to 33.6K bps.
  3. V.90 uses PCM (pulse code modulation) technology, signal level will be very sensitive to affect the connection speed. So, PABX or distant connection will damage the protocol and degrade to V.34plus.
• Can I upgrade my modem to V.90?
  Please check the manufacturer's web site to see whether your modem can be upgraded to V.90. If your modem can be upgraded to V.90, you can download the V.90 firmware code from the manufacturer's web site.
• Do I have to chose new ISP which will provide V.90 service?
  To make V.90 connection possible, your ISP must support V.90. All of ISP will gradually upgrade their service to provide 56K connection based on new ITU standard, no matter they are using K56flex or X2 technology. When your ISP starts to provide V.90 service, you can upgrade your modem firmware to ensure the best performance. If you are impatient, you can change your ISP if they do not support V.90 right now.
• I had a K56flex connection at 43Kbps. Why is the modem connecting at less than 33.6Kbps after upgrading to V.90 firmware? What should I do?

  There are two possibilities that your modem can not enjoy real V.90 performance.

  1. Remote ISP compatibility: After upgrading your modem to V.90 firmware, your modem can only establish the connection with ISP either by V.90 or V.34 standard (33.6 Kbps). That is, K56flex is no longer supported by your modem so that you may have connected with your K56flex ISP or X2 ISP by V.34.
  2. Connection environment, please refer to another FAQ.

  You can use the old K56flex firmware if your ISP does not support V.90.

• What should I do if my modem cannot achieve a good connection speed?
  1. Please check the protocol of your ISP. Are they using K56flex X2 or V.90 protocol. Your modem should support same protocol. If the protocol does not match, the connection speed will be less than 33.6K. If your ISP has upgraded to V.90, you may need to upgrade your modem firmware to V.90 too.
  2. If possible, please dial to another ISP or dial at different hour which is not busy in your country. You can use your telephone to check if your ISP is busy or not.
  3. If you have another modem, please use it to double check the telephone line quality
• Why my 56K modem can not reach to 56K bps?
  The connection speed is decided by both side modems and the telephone line quality. V.90 uses PCM (pulse code modulation) technology, signal level is very sensitive and line quality affects the connection speed a lot. Frankly speaking, 56K bps is idea speed in lab which the telephone line condition is well controlled by equipment. In real world, most of the 56K modem can reach 40K bps. If your connection is below 33.6K bps, make sure that the ISP is support V.90 and your modem have update to V.90 Firmware.
• What's the difference between a Diva ADSL USB and a Diva 2430/2430SE ADSL Modem?
  The Diva USB must be connected to a PC running Windows 98, Windows Me or Windows 2000 using a USB connection. It is a passive device which relies on software running on the PC to work. The 2430 and 2430SE ADSL modems have Ethernet ports as well as USB ports and they are 'intelligent'. Intelligent (in this context) means that they have their own processor and memory and implement the protocols needed to make the ADSL connection to the Internet themselves without relying on the host computer (see below for the difference between 2430 and 2430SE for more about this). Together, these features (Ethernet, intelligence) make it possible for the 2430 to work with any PC, including Apple Macs and Linux based-PCs, even with PCs that do not have USB hardware or operating system support. (PPPoE client software may be required with the 2430 - see below)
• Is the Diva ADSL USB supported on Apple Macs or on Linux PCs?
  Drivers are currently available for Windows 98/98SE/Me and Windows 2000, and Mac OS 8.6. Linux users will need to use a 2430 SE, or above, to use a Diva ADSL product.
• What's the main difference between a Diva 2430 and a 2430SE ADSL Modem?
  The 2430 is designed for use on so-called 'bridged' connections. In practice, this means that the protocol used is either PPPoE (PPP over Ethernet) or RFC1483B
  When the 2430 is used with PPPoE, the user's PC must run PPPoE client software
  The 2430SE is designed for both 'bridged' and 'routed' connections (including PPPoA - PPP over ATM)
  The 2430SE includes both PPPoE and PPPoA client software built-in.
  This means that the 2430SE can be used on more types of connection than the 2430 and it always operates independently of the user's PC. You don't need to run any client software on the PC.
  Anything else different?
  While the 2430 can, depending on the ADSL service, support two PCs simultaneously (one on USB and the other on Ethernet), the 2430SE only supports one PC (either USB or Ethernet).
  Security: The 2430SE protects your PC against intruders on the Internet by implementing a simple firewall.
• Why isn't the Diva 2430 ADSL Modem listed on some Eicon regional product pages?
  The 2430 is designed for use on so-called 'bridged' connections such as PPPoE (PPP over Ethernet).
  Bridged protocols were frequently chosen by 'early-adopter' ADSL service providers; many later implementations chose to use 'routed' protocols like PPPoA
  If only routed protocols are used by all available ADSL services in a country or territory, then Eicon does not offer the Diva 2430 ADSL Modem in that country or territory.
  Example: in the UK, all current ADSL services use PPPoA, so the 2430 is not used in the UK. However, since the 2430SE supports PPPoA it is used in the UK.
• What's the difference between the Diva 2430SE ADSL Modem, the Diva 2430 IG, and the Diva 2440 ADSL Router?
  The 2430SE is a single user device, and the 2440 is a multiple user device. The Diva 2430 IG is an enhanced version of the 2430SE that allows up to four PCs to connect to the Internet via ADSL.
  The Diva 2430 IG is currently available only in certain territories.
  When the 2440 is connected to a LAN via an Ethernet hub, multiple PCs can be connected to the Internet using the NAT firewall/ router built-in to the 2440, using only a single IP address on the Internet.
  This makes the Diva 2440 ADSL Router an ideal way for a SOHO (small office/home office) network to make maximum use of an economical ADSL connection.
• Do Eicon support ADSL over ISDN?
  Eicon has demonstrated ADSL over ISDN operation using the G.992.2 Annex B standard. Currently shipping products do not support ADSL over ISDN.
• How can I send a fax by ADSL
  The simple answer is that it is not possible.
  The reason is that an ADSL connection may share the standard telephone wiring, however, ADSL itself is only connected to the Internet. Since a Diva ADSL modem only accesses the ADSL connection, it too is only connected to the Internet.
  However, one of the main advantages about ADSL is that it runs in parallel with the ordinary analogue telephone service, and a conventional fax modem connected to the telephone port on the splitter will still work.
  Alternatively, use can be made of the various Internet-based fax-sending services available on the web. (Try searching for something like "internet fax service" using your favourite search engine on the web).
• Can VPN clients pass through the Diva ADSL 24xx Series modems?
  If the VPN client in question can work through a NAT Router then it should work. Many recent offerings from some of the most popular VPN Client suppliers have a UDP-based client which will pass through the firewall built-in to the 24xx series modems. Consult your VPN provider to see if the VPN Client can be configured or supplied with this type of setup. There may be a checkbox within the setup program for the VPN Client which allows it to pass through a NAT Router, for example. The NAT Router built-in to the 24xx series allows only TCP, UDP, GRE, and ICMP protocols through. Any other protocols are silently dropped for security reasons. As an example, the Eicon Networks 'Safepipe' VPN Client product works fine through the NAT Firewall on the 24xx series ADSL modems.
• Do I need any special phone line to use with my modem connection?
  The most common modem connection problems with analogue modem connections are phone line related. Check your phone line. Today's phone lines were initially designed to carry analogue voice signals, not digital data. Modem devices enable data to be transmitted over these lines by converting (or MODulating) the digital data streams from the computer into an analogue form that can be sent down a phone line. At the receive end of the line the modem then DEModulates these analogue signals coming in from the telephone line, reconverting them back into data. Unfortunately, the faster information gets transmitted down the phone line, the more susceptible the whole process becomes to line noise. Today’s V.90 modems requires good quality, low noise phone line connections to be able to consistently transfer data at 53Kbps. Poor connections and noisy lines will degrade the performance of the modem connection.
  Modern modem technology is sophisticated enough to deal with this degradation gracefully. When presented with a noisy line connection, the modems at each end renegotiate the speed at which they transmit and receive data. The result is a drop back in connection speed. The success of this process is largely dependant on the quality of the modems at each end. Also if the noise is sporadic or comes in bursts, then data being sent over the line may be corrupted during transmission. The modem receiving the data will detect the damage and request the transmitting modem to resend the information. The result is that while the reported connect speed of the modem may remain high, the actual data transmission speed may be significantly reduced due to the continual need to resend data.
  In the worst case, a poor line connection will cause the modems to disconnect from the line, or it may prevent the modems from establishing a connection at all. Different modems are better at dealing with noise than others, and again cheaper lower quality modems can exacerbate the problem. So if you having connection problems the first step always is to check your phone line:

  • The phone wiring within your premises can effect on your Dial Up Networking and Internet modem connection. It is worth trying to eliminate sources of line noise. Listen to the phone line during voice conversations. Does the line sound clear?
  • Sometimes the noise can originate in your own home or office. If you are using a long phone extension cord, try a shorter one. Make sure the phone line is not near any potential noise source, such as a monitor. And don’t operate your computer with the case open, as the case shields the noise created by the computer. Other noise sources could include desk fans, fridges, washing machines — the list goes on. Finding the source of noise is basically a process of elimination. Make sure the modem is at least three feet away from any fluorescent lamps. The electrical static generated by the fluorescent light may interfere with your modem connection. Electronic dimmers also radiate signals. Make sure these are off, or at least at full intensity.
  • Problem can arise when you have other equipment on the same phone line as the modem. Avoid using a line splitter, a duplex adapter, a coupler or anything other than one continuous cable between your wall jack and your modem. Try disconnecting any other telephones, answering machines, fax machines and modems on the same phone number to see if performance improves. You may have, for instance, a poor cable on a telephone handset that doesn't stay entirely "on hook." A single uninterrupted connection between the jack and the modem often improves performance.
  • Interference can come from the oscillators or transmitters in radios or television sets being near your modem. Some cheap modems (and televisions) are not properly shielded when manufactured. If you notice problems when a television is turned on or when a radio transmitter is activated, then you have a shielding problem. Monitors can also emit significant electro- magnetic fields. This can also interfere with an improperly shielded modem. Never place a modem on top of a TV or video display monitor. If you suspect this type of interference is causing your problem, try orientating the modem and its cables in different positions to see if that helps.
  • Placing an internal modem close to a source of internal computer radiation can induce problems into the modem's phone amplifiers. Try moving the modem to another PC slot to minimize this problem. Make sure your computer equipment is FCC Part 15 approved. This means that the computer and components have been tested and meet standards that insure your equipment will not adversely affect the operation of other electronic devices (such as modems, computers, TV's and radios).
  • Avoid using modems on phone lines that are switched through your office PBX as this can cause problems.
  • If you have call waiting on your telephone line, disable it.
  • If possible, try your modem on a computer in another location, or try someone else’s modem on your computer. Try dialing another ISP (perhaps using a free introductory offer kit).
  • Sometimes faults at your local telephone exchange can cause connection problems. In such a case the quality of the connection will vary. Hanging up and redialing usually fixes the problem. However, in this instance the consistency of your problem would suggest that this is not the cause. Lastly, if you've established that phone line inside your office are satisfactory but the line performance still is a problem, then call your telephone company and get them to test the state of your telephone lines. Most carriers undertake to make all their lines capable of at least maintaining a 9600-baud connection.
  • Selective interference can occur when you call only certain numbers or exchanges. Your telephone company routes signals from local exchanges/central offices to other exchanges/central offices. Sometimes certain exchanges cannot connect to others without line noise problems. If you see a pattern like this, notify the telephone company of the problem. Cross-talk on a telephone line can cause serious modem communication problems. Your telephone company is obligated to check out service problems that can be specifically isolated to certain exchanges or conditions. Do not be put put off if the telephone company tries to sell you a digital (e.g. ISDN) service or a dedicated (leased) line as the solution. They generally have an obligation to provide a basic level of service.
• My modem dials out but it won't successfully complete the connection.
  There are a number of problems that can prevent your modem out dialing successfully:

  • If your modem fails to make a particular connection then the problem may well be with the telecom line or with the modem at the other end. Retry making the connection (and if possible try making the call with a standard phone connected to see if you can establish a voice call over the line).
  • Sometimes problems arise because of incompatible modems at each end. In theory all modems meet the international telecommunication standards and they can be assured of speaking to each other. With popular name brand modems this is the case. However there are many cheap modems on the market that may not reliably interconnect.
  • Also check the modem configuration at the other end. If the modem at the other end does not have error correction then you will need to disable error correction at your PCI-RAS end by issuing to each modem port:
    AT\N0
  • Another common problem with failure to connect is timeouts. High-speed modems can require a long time to recognize, negotiate and properly connect to other modems. Ensure you are allowing at least 60 seconds per call attempt. Also set your modems S7 register to = 255. By default, S7 allows only 30 seconds of waiting before disconnecting. Setting S7=255 allows your communication program to have complete control over the process.
• Problem: My modem link loses data with high speed connections
  This problem can have a number of causes:

  • The most common is a poor dial up connection so redial and check the line condition.
  • Ensure that your modem and dialer program are also using hardware flow-control (RTS/CTS ON).
  • For Wave modems make sure the modem cable you are using supports hardware flow-control.
  • Set the COM port speeds to run at (or faster than) the maximum modem connect speed. e.g. 38400 is a good port speed for a 33.6kbs modem links but use 155kbps for 56K connections.
  • For Wave modems ensure the serial port it is attached to has at least a16550 serial UART device.
• Will my modem work with call waiting?

  Unfortunately the tones generated by the exchange to inform you that another call is coming in, will interfere with the modem communication, and may drop the connection. To get around this problem simply turn off Call Waiting on your phone before you dial out with your modem.

  To turn it off select the Modem device in the Control Panel. Then in the Dialing Properties add the command to turn off call waiting to your modem's dialing string by checking Disable Call Waiting. This will prevent call waiting from hanging up your connection!

  In USA the general command to add to your dial-up string is *70, (i.e. asterisk 70 comma). In Australia the general command string is *43# (i.e. asterisk 43 hash) and to turn the Call Waiting back on just dial ‘*43#’ when you are finished. If you are unsure check with your telephone company or a phone book for the appropriate command characters.

  If possible, try your modem on a computer in another location, or try someone else’s modem on your computer. Try dialing another ISP (perhaps using a free introductory offer kit).

• Can I use my modem through a PBX?

  PCI-RAS modems were designed to be used on the standard 2-wire analogue PSTN telephone system. If your PBX conforms to this specification for its internal lines then the modem will work properly. Most PBX’s also require you to place a ‘0,’ or a ‘9,’ in front of the number to get an outside line.

  PCI-RAS modems will not work on Digital PBX systems and may be damaged if connected to such a network.

• How do I determine if my modem supports fax Class 1 or Class 2?

  All current models of PCI-RAS modems support both fax Class1 and fax Class 2. However the Rockwell modem chip hardware and firmware used in these products sometimes only offer fax Class 1 support (particularly the early revisions of new releases). To determine the fax capabilities of your PCI-RAS modem, access the port using a terminal emulator program (e.g. HyperTerminal in Programs/Accessories in Windows NT/95/98) or use cu under Unix, and issue the following commands:
  AT+FCLASS=?
  If the modem is Class 1 then the response from the modem to this command will return a string 0,1,1.0. If the modem is Class 1 and Class 2 the response will be 0,1,2, 1.0
  If the modem is a Class 2 modem, then you can issue further AT commands to determine the fax microcode revision etc.
  AT+FMFR?
  This will return Rockwell as the name of the manufacturer of the chip set. Note that you may need to type AT+FCLASS=2 before the FMFR command will be accepted by the modem.
  AT+FMDL?
  This will return the model number of the Rockwell modem chip used on the PCI-RAS card (e.g. AC/V34 for RA4001).
  AT+FREV?
  This will return the firmware revision level for the PCI-RAS modem (e.g. V2.05-V.34_ACF_DSI). This same information is returned by the ATI3 command.
  AT+FBUF?
  This will return the current internal fax buffer settings within the modem, including high water XOFF and low water XON levels.

• What is Data Compression? Error Correction? Flow-Control?

  Data Compression
  Data compression is a system by which the modem tries to compress the data before sending it via the phone line and thus improve the throughput of the transmission. PCI-RAS modems use the ITU-T V.42bis protocol for data compression. It can give a throughput increase of up to 400%. This means that although for a modem that can only go as high as 33600 bps on the telephone line, you can achieve theoretical effective speeds of 115,200 bps. In most cases with normal files that have not been compressed already you can get reliable transmission rates of about 50,000 bps.

  Error Correction
  Error correction is a system by which modems try to eliminate errors on the line. The data is encoded in a certain manner that allows errors to show up clearly. When this happens the modem will automatically ask the other end to resend the data. This helps to ensure error free data transfer between devices. A by product of this encoding is that the modem makes more efficient use of the line and can thus get up to about 110% of rated raw throughput from the modem. PCI-RAS multi-modems support the ITU-T V.42 specifications for error correction protocols.

  Flow-Control
  Flow Control is like a set of traffic lights between the modem and the computer. Because the modem does not know what the computer is doing at any given time and vice versa, there needs to be a system in place to let each other know when they are busy. Flow control allows the computer (or modem) to stop the flow of data while it is busy doing other operations and then start it back up again, thus not lose any of the data being sent.

  There are 3 types of flow control in common use at the moment. They are No flow control, XON/XOFF (also known as Software) and RTS/CTS (also known as Hardware). All high-speed modems require a form of flow control whether XON/XOFF or RTS/CTS. The Banksia Wave modem defaults to RTS/CTS as it is deemed to be the most reliable. PCI-RAS modem ports are all hardwired with RTS/CTS. The PCI-RAS communications engine manages this flow control at the chip level on the card - so there is no chance of losing data.