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- Can I use 5v I/O circuit logic levels with 3.3v models?
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- Yes, however the modem inputs (TXD, DTR, RTS and Reset) need a 1K resistor in series when interfacing to 5V logic. Also, check the specs to make sure the modem outputs are high enough to drive the inputs of the logic family on the embedded system. Our minimum high output spec must exceed the minimum high input spec of the 5V logic circuit.
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- Models: MT5634SMI-ITP-92
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- Can Multi-Tech recommend manufacturers and part numbers of chip sockets, fuses, capacitors, and resistors to finish design work?
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- The developer’s guide has some recommendations.
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- Models: MT5634SMI-ITP-92
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- Do I need to design in the recommended capacitors and ferrite in the Tip/Ring circuit to prevent EMI leakage out the phone cable?
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- This is good design practice. You may have trouble gaining system approval for EMC without these components added to your design.
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- Models: MT5634SMI-ITP-92
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- Does Multi-Tech provide any SocketModems that go into a low power “sleep” mode?
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- Yes all models.
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- Models: MT5634SMI-ITP-92
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- Does Multi-Tech provide the modem script for my Mac?
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- Yes. If you have a Multi-Tech modem or terminal adapter, you can download the scripts free from our FTP server (ftp://ftp.multitech.com/mac-scripts). If you have a Multi-Tech USB modem, an installer containing the modem script and system extension is provided on the CD that shipped with the modem.
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- Models: MT5634SMI-ITP-92
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- Does Multi-Tech provide the system extensions (drivers) for my Mac?
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- Yes. If you have a Multi-Tech USB modem, you can download the system extensions free from our FTP server (ftp://ftp.multitech.com/mac-scripts). The system extensions are bundled in the same file as the modem scripts. The serial modems and serial terminal adapters do not require system extensions.
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- Models: MT5634SMI-ITP-92
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- Does the modem “Reset” on power up?
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- Yes, it is a soft reset.
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- Models: MT5634SMI-ITP-92
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- How do I design my LED driver circuit?
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This can be handled in one of two ways:
- All of the serial models (with the exception of the MT5600SMI and MT3400SMI) have an LED driver designed into the module. You simply add the pull-up resister and LEDs to finish the design.
- For all other models, you can add an external driver chip to connect to the serial I/O which in turn drives the LEDs.
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- Models: MT5634SMI-ITP-92
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- How do I put the modem module into voice mode?
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- Use the AT+FCLASS commands. For details refer to the developer’s guide.
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- Models: MT5634SMI-ITP-92
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- I have a V.90 SocketModem solution and it negotiates tones but does not connect. What do I do?
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- If Orginating a call: Disable the V.90 protocol on the SocketModem with the appropriate "AT" Command (Answering modem pool is NOT a digitally terminated V.90 modem pool). Next, we suggest that you disable "calling tones" with the appropriate "AT" Command.
- If Answering a Call: Disable "V8 tones" with appropriate AT command.
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- Models: MT5634SMI-ITP-92, MT5634SMI-P-92, MT5634SMI-P-HV-92, MT5634SMI-P-ITP-92, MTIFM, SC56H1
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- The SocketModem is not responding to AT commands. What do I do?
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- First, check the supply voltage to the modem. It should be either 3.3V DC or 5V DC.
- Next check for the presence of DTR (input to the modem). If it doesn’t have this, it will not function.
- Identify and re-evaluate Transmit/Receive and CTS/RTS to make sure they are connected properly. Often times, inputs and outputs can be swapped based on interpretation. The modem is considered a DCE device.
- Lastly, if you’ve gone through all steps above, disable flow control.
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- Models: MT5634SMI-ITP-92
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- What are the minimum I/O control signals required for the modem to work?
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- TD, RD and Gnd
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- Models: MT5634SMI-ITP-92
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- What is the difference between line speed, serial speed and auto baud?
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- Line speed – is the modem negotiation rate (ie. 2400 baud)
- Serial speed – is the speed between the DTE and the modem. This can be locked in or dynamically adjusted.
- Auto baud – is the ability of the modem to connect at 300 baud to the maximum line speed available on the modem (ie. 56000 baud). This can automatically adjust during modem negotiation.
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- Models: MT5634SMI-ITP-92
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- What is the minimum required pulse length for “DTR drop” to disconnect the modem?
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- 100ms
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- Models: MT5634SMI-ITP-92
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- What is the minimum required pulse length on the “Reset” pin?
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- 50 – 100ms
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- Models: MT5634SMI-ITP-92
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- What is the polarity of Tip & Ring?
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- The SocketModem is not sensitive to Tip and Ring polarity.
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- Models: MT5634SMI-ITP-92
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