How do I setup a Modem and the EDS to allow character mode dialup connections?

---

To setup the EDS to receive an incoming character mode dialup connection, set the modem so that it does not echo commands and does not send result codes. This is needed to keep the modem from sending a "Ring" to the EDS when you call in.

You can send this string to the Modem (Hayes Compatible) by sending the following modem commands into the Modem's serial port:

AT&F
AT S0=2 E0 Q1 &W &Y

The first line resets modem configuration to factory profile.

The second line tells the modem to answer on the second ring, do not echo commands to the host, do not send result codes to the host, write settings to NVRAM, and ensure that the default power on profile is the same one we just wrote to.

Your modem may need different commands.  Please see the documentation for your modem for information on AT commands.  However, these commands are pretty standard.

You can send these commands to the Modem while it is connected to the EDS with the following procedure:

Telnet straight to the Modem through the EDS's port using the TCPPort assigned to the port your Modem is on. You can find the correct TCPPort for the port your Modem is on by adding the number of the port to 10000 (EDS Default Port Number).

For example:
Port 1 = 10001
Port 2 = 10002
Port 3 = 10003
etc.

Example:
To Telnet straight to a Modem on port 3 of the EDS from a Windows command prompt type:

telnet nnn.nnn.nnn.nnn 10003
(Replace the n's with the IP address of the EDS)

After connecting to the port, you should be able to type AT, hit enter and the Modem should respond with OK.

If you do not get an OK from the Modem, try typing AT&F and see if you get an OK.   If not, you may have a cable problem.

After verifying that you are communicating with the Modem, send the commands:

AT&F
AT S0=2 E0 Q1 &W &Y

After this, you will no longer get an OK from the Modem since you turned off result codes.

At this point, you can close your telnet session to the Modem.

Now, follow this procedure to setup the EDS using the Web Manager Interface by opening an web browser session to the IP address of the EDS:

• Select Line, then the line number you have the modem connected to, then select command mode.
  • Choose Always, then submit
• Select Tunnel, then the tunnel number you have the modem connected to, then select Accept mode.
  • Choose enable, then submit
• Select Connect Mode for the same Tunnel number.
  • Choose disable, then submit
• Select Disconnect Mode for the same Tunnel number.
  • Choose disable, then submit
• Select CLI, then Configuration.
  • Enter an Enable Password, then submit. This inhibits unauthorized logins. (You can enter up to 32 characters)

You can use Tera Term or Hyperterminal to dial up to the modem connected to the EDS using the ATDT command and the phone number of the modem connected to the EDS.

To disconnect your call you will need to use the +++ command from you dial up session to return to the modem command mode and then type ATH to disconnect the dial up session.

Cabling

With the EDS4100 you can use a standard modem cable designed to connect to a PC's DB9M Com port.  The EDS4100's serial ports use the same pinout as a PC's Com Port.  Modem cables are widely available, or you can order one from Lantronix, part number 500-163

An EDSxPR serial port requires an RJ45 to DB25M adapter for most modems.  The diagams below assume you are using an RJ45 to DB25 or DB9 adapter with an RJ45 to RJ45 network patch cable:

Modem with DB25 serial connection:

                              LTRX Part # 200.2073

             Cable                  Adapter   

RJ45        (Straight)         RJ45         DB25    Signal

RTS 1     1-------------1       1-------------4     RTS

DTR 2     2-------------2       2-------------20    DTR

TX+ 3     3-------------3       3-------------2     TXD

TX- 4     4-------------4       4-----|      

RX- 5     5-------------5       5-----|-------7     Signal Ground

RX+ 6     6-------------6       6-------------3     RXD

DSR 7     7-------------7       7-------------8     DCD

CTS 8     8-------------8       8-------------5     CTS

Modem with DB9 serial connection:

Most serial modems use a DB25F connector, but if you have a modem with a DB9 connector here is how you would wire the adapter:

             Cable                  Adapter   

RJ45        (Straight)         RJ45          DB9    Signal

RTS 1     1-------------1       1-------------7     RTS

DTR 2     2-------------2       2-------------4     DTR

TX+ 3     3-------------3       3-------------3     TXD

TX- 4     4-------------4       4-----|      

RX- 5     5-------------5       5-----|-------5     Signal Ground

RX+ 6     6-------------6       6-------------2     RXD

DSR 7     7-------------7       7-------------1     DCD

CTS 8     8-------------8       8-------------8     CTS

When looking at the RJ45 socket with the notch for the locking tab facing down the pins are numbered 1-8 left to right:

                                  12345678 

                                 [||||||||]

                                 [        ]

                                 [__    __]

                                    |__|

---

[Originally Published On: 04/25/2007 09:29 AM]