Cell Phone Dial Up

[danish30]

"What happened to the modem? How does the lap top talk to the cell network?"

 

 

 

Try plug it in your laptop and cell, chances are that it will be detected and installed automaticly, then you will see a new modem device appear. If this happens then you are ready to go. If not, try to see if you can find a driver for your phone, maybe available on the manufacturers website.

 

 

 

"but their Cust Services want me to use their service through CS which does not support email."

 

 

 

You can use any internet service you like, just buy some internet card in your local shop and use that one.

 

 

 

"They are also encouraging me to use WAP??? which I assume is a means of using the cell phone to read and display mail which is the last thing I want to do. "

 

 

 

WAP is kind of a simplified internet protocol for cell phones, IMO it's rather useless. Don't get it if you have to pay extra. I have only used it a couple of times to check flight and train schedules, maybe 5 times in a year.

 

 

 

Best regards,

 

 

 

Danish30

[Guest]

You can read your mail via POP3 or IMAP with no problems. Sending mail is a bit more difficult these days (thanks to the spammers). You need to find a server to do SMTP for you, I'm not sure if CS offers one. I use my own server for sending mail which I programmed to accept SMTP connections from CS.

 

 

 

Many public mail services (like myrealbox.com) allow you to send mail after you have logged in via POP or IMAP first. That's an easy fix also.

 

 

 

I recommend myrealbox because it optionally supports IMAP which is vastly superior to POP and also offers web-based mail. And then there's stuff like mailforwarding and filters which make life a lot easier.

 

 

 

Hope this helps,

 

Xenna

 

 

[Guest]

Cheers! Confirm I should be able to dial into Loxinfo using the cell and Loxinfo's regular number and I should be able to use my regular mail account to send and receive.

 

 

 

Thanks for the help from all

[danish30]

Sure, should be no problem dialing and using your regular Loxinfo account.

 

 

 

Best regards,

 

 

 

Danish30

[Guest]

I have just tried Nokia.com which has to be one of the most useless examples of a web site I have come across. I tried contact details for their local office and believe it or not they dont appear to have an email address, no downloads and no customer services.

 

 

 

Am I looking in the wrong place or is this just Nokia.

[danish30]

Yes I agree with you, I never understood why they didn't just put the software for download at their website. I mean, you have to own a Nokia phone to have any use for their software.

 

 

 

Anyway, what model is your Nokia? Mine came with a cd with all the drivers and stuff when I bought it.

 

 

 

Best regards,

 

 

 

Danish30

[adikgede]

Here is the long and short of "What is GPRS?"

 

 

 

Most people can ignore the Linux and Ericsson bits.

 

 

 

from url=http://turtiainen.dna.fi/GPRS-HOWTO

 

 

 

LINUX GPRS HOWTO

 

 

 

Esa Turtiainen (etu@dna.fi)

 

Jari Arkko (Jari@arkko.com)

 

 

 

15th April, 2001

 

(Last update 25th January, 2002)

 

 

 

 

 

TABLE OF CONTENT

 

 

 

INTRODUCTION

 

QUICK START

 

ADVANCED CONFIGURATION

 

PROBLEMS IN GPRS TO INTERNET CONNECTIONS

 

PPP PROBLEMS BETWEEN LINUX PPPD AND GPRS CELLULAR TELEPHONE

 

PARAMETERS IN ERICSSON R520m GPRS PHONE

 

ERICSSON T39

 

CAN I CONNECT TWO GPRS TELEPHONES TOGETHER?

 

SECURITY PROTOCOLS WITH GPRS

 

COMBINING GSM DATA AND GPRS DATA WITH THE SAME SETUP

 

ROAMING ABROAD

 

SOME GPRS TERMS

 

LINKS

 

DISCLAIMER

 

 

 

 

 

INTRODUCTION

 

 

 

GPRS is a General Packet Radio Service, an add-on to GSM and TDMA cellular

 

telephone standards used all over the world. It allows (almost) always-on

 

Internet connections using GSM (or TDMA) telephones.

 

 

 

You need a GSM (or TDMA) telephone that has GPRS support to use the service

 

(for example, Ericsson R520m). Additionally, your operator must support

 

service and you must subscribe it.

 

 

 

PC ------ Telephone ------ Operator ------ ISP ------ Internet

 

PPP over IP over (GGSN) IP IP

 

IrDA/ several

 

Bluetooth/ tunneling

 

Serial protocols)

 

 

 

This howto describes how you can access Internet with your PC using a GPRS

 

cellular telephone as a modem. For you, it looks like you call to an ISP

 

but your telephone handles the connection and on the wireless network there

 

is just packets. Actually your telephone has a dual role: it acts like a

 

modem for you (you discuss with standard modem AT commands to create the

 

connection) but as well it acts like an ISP modem bank and access server.

 

Your PPP connection ends already on your telephone and the raw IP packets

 

are tunneled over the operator network into an ISP (often operator itself).

 

 

 

GPRS is able to relay several protocols but normally you are interested only

 

in a situation where you use PPP from the PC to the telephone and telephone

 

tunnels IP packets to an ISP to be delivered to Internet (or operator's WAP

 

service or your company intranet).

 

 

 

To create a connection, you first communicate with the GPRS cellular

 

telephone by a simple AT command set (it is exactly like a modem but a

 

little extended). The call command (ATD) is handled by the telephone and it

 

starts a PPP connection for you.

 

 

 

After that, the situation looks exactly similar as your computer is

 

communicating with an ISP modem.

 

 

 

 

 

QUICK START

 

 

 

Let's assume that you have an laptop and infrared connection to a GPRS

 

cellular telephone. You must have a GPRS subscription and you must know

 

an APN string used to access Internet from your operator's network.

 

 

 

Now you can start the connection by

 

1. Configure connection in your telephone using operators

 

parameters and CID=2

 

2. Set up infrared connection between your PC and telephone.

 

3. Call like to normal ISP using the modem in infrared port,

 

use telephone number *98*2#

 

 

 

and that is it. However, this may require some more explanation and

 

problem solving.

 

 

 

First, you configure some communication profiles to your GPRS phone. This

 

saves you some work because after that you refer to those profiles by using

 

number of the profile to be used (that is called CID). Let's assume that we

 

are using CID=2 (the default one (1) is often used for WAP connections). The

 

most important parameter for every connection is a string called APN. That

 

characterizes where you want to connect. You have to ask from your operator

 

what APN to use to access public Internet, in our case it is simply

 

"internet" (operator is Sonera). There are different strings to access WAP

 

gateway or company intranets.

 

 

 

Then you connect the phone. You can do that with an infrared connection (or

 

serial cable or Bluetooth). In any case, the phone looks like a modem that

 

is behind serial cable.

 

 

 

Then you start the connection exactly like calling an ISP. The easiest way

 

to connect is to use a special kind of telephone number. It is:

 

 

 

*98*2#

 

 

 

This starts PPP/IP connection to your telephone. Number 2 refers to CID

 

that you have assigned to accessing Internet on your telephone. If it is 3,

 

use telephone number *98*3# instead. If you use something that looks like a

 

normal telephone number, you are calling this number using ordinary GSM

 

data. Assigning CID numbers is telephone specific and it is explained

 

later.

 

 

 

Now you have a PPP connection open to your infrared port. Use it like

 

you had called an ISP using a modem. Some tricks may be needed because

 

the PPP implementation in a cellular telephone is naturally as minimal

 

as possible.

 

 

 

You likely need get a DNS server address and set it as your operator

 

recommends before you can resolve DNS names.

 

 

 

 

 

ADVANCED CONFIGURATION

 

 

 

The quick call using number *98*2# does not allow you to modify parameters

 

to your GPRS connection. A full range of parameters is available if you

 

use extended AT commands defined in ETSI TR 127 007.

 

 

 

To test these commands, you can try taking a terminal emulator connection to

 

the telephone. This works over infrared connection using the serial line

 

number that is assigned to the infrared connector (IrDA). (Note that, at

 

least in Ericsson R520m telephone, telephone does not start PPP negotiation

 

even after you start a valid connection - it waits for a valid PPP packet

 

from you.)

 

 

 

The basic GPRS commands start with +CG. To start a GPRS data connection,

 

you can use to following instead using *98*2# telephone number (you are not

 

able to give more commands after this!):

 

 

 

AT+CGDATA="PPP",2<CR>

 

 

 

Where <CR> is the end of line character "Carrier Return". Commands are

 

case insensitive.

 

 

 

Before giving the previous command you can give other commands to set

 

communication parameters. Most commands can be used to ask and set

 

parameters and in some commands you can ask for allowed parameter ranges.

 

For example:

 

 

 

AT+CGDCONT? (ask CID parameters in GPRS cellular phone)

 

AT+CGDCONT=... (set CID parameters in GPRS cellular phone)

 

AT+CGDCONT=? (ask parameter ranges)

 

 

 

+CGDCONT handles those parameters that you normally modify using

 

GPRS cellular telephone menus.

 

 

 

Command +CGQREQ sets quality parameters for the connection.

 

 

 

Command +CGTFT would set some more interesting parameters in IP

 

connections but it seems to be not implemented in Ericsson R520m.

 

It could set for example IPSec encryption.

 

 

 

Note that telephone number *98*2# is handled differently than the normal

 

telephone numbers in your GPRS cellular telephone. Nothing happens if you

 

manually try to call this number using telephone keyboard.

 

 

 

There is another telephone number *99# as well. It takes more parameters

 

and allow X.25 etc. data calls. However, if you use PPP/IP communications,

 

there is not much use of extra parameters in *99# command.

 

 

 

ETSI TR 127 007 is available from ETSI web site http://www.etsi.org by

 

registering yourself. It is around 160 pages long. This document used to

 

be quite expensive but currently it is freely downloadable.

 

 

 

 

 

PROBLEMS IN GPRS TO INTERNET CONNECTIONS

 

 

 

Wireless transport always creates it's own challenges in communications.

 

GPRS is still first generation of packet based public telecommunications

 

service.

 

 

 

The worst problem is that the latency is pretty bad. The best pings are

 

about one and half seconds.

 

You don't want to use interactive applications one character at time over

 

GPRS. SSH is especially slow because secure authentication requires very

 

many round-trip communications.

 

 

 

All the DNS queries, even to the operator DNS server will take more than a

 

second. You likely want to put a local DNS cache program to your PC.

 

 

 

In GPRS you are likely behind NAT (Network Address Translation). All your

 

connections to Internet seems to come from one operator's computer. That

 

means for example that IPSec security protocol or H.323 or SIP signaling of

 

multimedia applications won't work.

 

 

 

Mailer that are based on SMTP do not normally accept any mail due to spamming

 

misuse or this feature. Therefore you have to get SMTP mailer address from

 

your operator to send mail. Our current provider (Sonera) does not offer

 

that yet.

 

 

 

 

 

PPP PROBLEMS BETWEEN LINUX PPPD AND GPRS CELLULAR TELEPHONE

 

 

 

There are some problems in PPP protocol used in GPRS telephone. (Some of

 

these notes may be specific to Ericsson R520m telephone.)

 

 

 

 

 

Normally you want that you are able to start communications with command

 

 

 

pppd call gprs

 

 

 

This requires that you put the appropriate line options to file

 

/etc/ppp/options.ircomm0 (that is used automatically when ppp is started to

 

/dev/ircomm0). Note that options in /etc/ppp/options and in ~/.ppprc

 

interfere with these settings. (Note the evaluation order of these files!)

 

Additionally the file /etc/ppp/peers/gprs should define the gprs operator

 

and /etc/chatscripts gprs should define how to make the call. Naturally,

 

this is optional and the commands can be given directly as well.

 

 

 

There is no hardware flow control or carrier detection in the GPRS cellular

 

telephone - at least in infrared protocol. You must turn them off. In PPP

 

option files use options:

 

 

 

-crtscts

 

local

 

 

 

to turn off waiting of carrier detect or flow control signals.

 

 

 

You must use CHAP authentication protocol and check the information in

 

chap-secrets - although passwords are not necessarily checked in network.

 

If you turn authentication off, GPRS telephone suggest some protocol that is

 

not supported in Linux PPP. This breaks the connection attempt.

 

 

 

The network does not answer Linux PPP echo request. This means that in the

 

default configuration the connection will be shut down in about two minutes!

 

PPP echo requests must be turned off. You must comment out the entries:

 

 

 

# lcp-echo-interval 30

 

# lcp-echo-failure 4

 

 

 

Note that I am not aware how to disable these if they exist in any

 

PPP configuration file. Setting them as 0 does not disable them.

 

If echo is set on in /etc/ppp/options you can not disable them in

 

/etc/ppp/options.ircomm.

 

 

 

When you debug the connection, you want to add options

 

 

 

debug debug debug

 

nodetach

 

 

 

To get interactive messages to console. Note that you need

 

to write debug three times to get enough messages.

 

 

 

To optimize connection, you should add packet size to as large as possible.

 

GPRS is able to handle 1500 byte packets. Your latency is bad anyhow, so

 

there is no need to use small packets. (Actually, it caused a lot problems

 

when the MTU was changed. Don't touch the default before you get the

 

connection up.)

 

 

 

To be checked:

 

- best compression combination

 

 

 

A working chatscript (/etc/chatscripts/gprs) is:

 

 

 

...........

 

 

 

A working GPRS peer definition (/etc/ppp/peers/gprs) is:

 

 

 

...........

 

 

 

And putting all this together you can call Internet through GPRS cellular

 

telephone by simply writing "pppd call gprs". You can always check the

 

connection status by

 

 

 

% ifconfic ppp0

 

....

 

 

 

Naturally you need plenty of IP parameters right to get connection up but

 

they are general to any Internet connection. Especially boring is to change

 

DNS servers in /etc/resolv.conf to those that operator suggests. (Note that

 

there is a new feature to fetch DNS servers from network inside PPP protocol

 

(option usepeerdns) but GPRS does not seem to support that.)

 

 

 

 

 

PARAMETERS IN ERICSSON R520m GPRS PHONE

 

 

 

Normally, you left all the connection parameters as defaults except APN.

 

That means that user name and password are empty (and you don't want to send

 

password at all) and you don't set fixed IP address. Quality of service

 

parameters are normally "as subscribed".

 

 

 

First, you configure some communication profiles to your GPRS phone. This is

 

necessary as the profiles will be used as we bring up the gprs connection

 

later. The profiles are referred to by a number called the CID. Typically we

 

will use either CID=1 or CID=2, maybe most often the latter as the number 1

 

may have been reserved for WAP. The most important parameter for every

 

connection is a string called APN, which identifies the network we want to

 

connect to. You have to ask from your operator what APN to use to access

 

public Internet, in our case of the Sonera, it is simply "internet". There

 

are different strings to access WAP gateway or corporate intranets.

 

 

 

Here's how to set up the profiles for your Ericsson R520m phone. Go to

 

"Settings" and scroll down to the end of the menu and pick "Data comm.".

 

Then pick "Data accounts". You might already have a suitable account here,

 

but if not go ahead and create one. (Typically, a WAP profile would have the

 

string WAP in its name, and these can't be used.) Creating a new account

 

happens through pressing "Add account". Here you can simply specify the APN,

 

the username and password can be left as empty, and everything else to

 

reasonable defaults. In the case of Sonera, we need to set the APN to

 

"internet" and the name of the profile should be "INTERNET". As the creation

 

has been performed, go back to the "Data accounts" menu and pick the account

 

you just created and press Yes. A menu appears, and you will see at the end

 

the CID value, typically either 1 or 2. Memorize this.

 

 

 

The init string for the telephone is (from Windows settings file erim520.inf

 

in associated CD ROM):

 

 

 

AT &F<cr>

 

AT V1E0S0=0&D2&C1<cr>

 

AT +CMEE=1<cr>

 

 

 

This looks like more adapted to GSM data connections but we have used the

 

same one to initialize GPRS connections.

 

 

 

There are some settings where you should set default to GPRS to ensure that

 

GPRS is used whenever possible. However, they are not critical in PC use.

 

 

 

Note that in this telephone, infrared connection is not on unless you

 

disable Bluetooth. The only warning is that you have just Bluetooth icon on

 

the display but not infrared icon (although you have enabled infrared).

 

 

 

The only way to know that the GPRS connection is on is to ask status of the

 

phone, for example using the volume button on the side of the phone. As the

 

last line there is a mention on GPRS if it is on. I don't know any way to

 

find out how much data you have transferred in the current session.

 

 

 

The telephone is able to run on 115200 kbps in infrared interface. There is

 

no need to limit speed of infrared to lower speed like in some other

 

cellular telephones.

 

 

 

The speed of connection with these settings is around 3.2 kBps (26kbps).

 

There may be some other settings to increase speed (we are working on that).

 

 

 

Ping latencies with GPRS are:

 

 

 

...

 

 

 

 

 

ERICSSON T39

 

 

 

There is a problem in Ericsson T39 telephone and current pppd software

 

in Linux. It does not to work because Linux is bit too fast. There

 

is a patch that adds some delays in

 

 

 

http://turtiainen.dna.fi/ppp-2.4.0-patch-t39m

 

 

 

for PPP 2.4.0 by Tommi Linnakangas (Tommi.Linnakangas@iki.fi). This

 

should be quite straightforward to modify manually as well.

 

 

 

 

 

CAN I CONNECT TWO GPRS TELEPHONES TOGETHER?

 

 

 

Unfortunately no. All the connections must be started from the

 

telephone. You must use servers in the network.

 

 

 

At theory there could be some proxy that could help here but we

 

are not aware of such an application.

 

 

 

 

 

SECURITY PROTOCOLS WITH GPRS

 

 

 

Likely all operators use network address translation or NAT

 

to change your IP address on the edge of the network. This

 

means that standard IPsec protocol does not work with GPRS.

 

There are extensions that allow that but still they do not

 

interoperate between different IPsec implementations. Most

 

vendors do not support it yet.

 

 

 

SSH works with GPRS but it is quite useless in interactive

 

use. All security protocols use challenge-response authentication

 

that requires several roundtrips. If packets are lost, timeouts

 

affect badly performance. Starting SSH connection requires tens

 

of secons.

 

 

 

 

 

COMBINING GSM DATA AND GPRS DATA WITH THE SAME SETUP

 

 

 

...

 

 

 

 

 

ROAMING ABROAD

 

 

 

When you roam abroad, all the settings should remain the same.

 

Especially, APN should be globally unique.

 

 

 

With our Sonera connection, roaming to Norway should work but

 

we have not tried it (yet). Follow the Sonera links for more

 

info.

 

 

 

 

 

SOME GPRS TERMS

 

 

 

Here are some important GPRS terms. Some of there are not used in this

 

howto to keep things simple. However, you need these if you read any GPRS

 

descriptions - writers of this material love acronyms. Here are two groups

 

of terms: important ones for this scenario and less important ones (network

 

internal terms).

 

 

 

Important terms:

 

 

 

GPRS

 

General Packet Radio Service

 

APN

 

Access Point Name. Name of the ISP, Operator WAP gateway or

 

company intranet.

 

GGSN

 

Gateway GPRS Service Node. Node that relays IP packets to ISP,

 

Operator WAP gateway or Company intranet. APN actually identifies

 

one interface in one GGSN.

 

PDP context

 

This is synonym for your IP tunneling connection to ISP

 

ISP

 

Internet Service Provider. That operator that gives you

 

general Internet connectivity, DNS services, email services

 

and even your IP address. Often the same as your GPRS operator

 

but not necessarily.

 

MS

 

Mobile Station. Your cellular telephone.

 

MT

 

Mobile Terminal. Your PC.

 

 

 

 

 

Less important terms:

 

 

 

PDP

 

Packet Data Protocol. (IP in this case.)

 

IMSI

 

International Mobile Subscriber Identity. Your subscription

 

and identity information related to subscription. There is no

 

special GPRS IMSI but it is the same as your GSM IMSI.

 

GTP

 

GPRS Tunneling Protocol. The protocol used to tunnel IP packets

 

from your location (SGSN) to GGSN.

 

SNDCP

 

Subnetwork Dependent Convergence Protocol. The protocol used to

 

tunnel IP packets from your terminal to your location server (SGSN).

 

SGSN

 

Serving GPRS Service Node. The node that keeps track of you when

 

you are on it's location area.

 

 

 

 

 

LINKS

 

 

 

http://www.etsi.org

 

http://mobileinternet.ericsson.com

 

http://www.sonera.fi/gsm/gprs/gprs_faq_etusivu.html

 

http://www.sonera.fi/gsm/kuuluvuus/ulkomailla/index.html

 

http://www.3gpp.org

 

http://www.mobilegprs.com

 

 

 

 

 

DISCLAIMER

 

 

 

Note that although we both work for Ericsson we have not used or even

 

received any information from Ericsson for this HOWTO. We just happened to

 

be among the lucky ones to receive Ericsson R520m telephones among the first

 

ones and wanted to share the experience. Terminology used in this howto is

 

meant for more clarity than accuracy. Esa is not affiliated with the

 

Finnish operator DNA - the mail address dna.fi is the older Domestic Network

 

Association, the operator is dnafinland.fi.

 

 

[adikgede]

The software is at the Nokia web site. However it is probably easier to use Google to find it than to try to navigate Nokia's web site. Search for "Nokia PC Suite" (Its a big download. It may be on the host FORUM.NOKIA.COM. It might be easier to get someone to post the driver for your model at the newsgroup alt.cellular.nokia or find help at WWW.CLUB.NOKIA.COM. My wife has a Nokia 8310 and the software suite totaly foobarred her phone book. Luckily we dumped the phone and the SIM to a file before we started. The software suite did not install the drivers for our phone on the PC I think you are supposed to have the phone recognized by the IR port when you install the software. I haven't ph*cked with Nokia's PC Suite since because the Linux GPRS package was only 287kb and it worked for our Ericsson and Nokia phones without all the megabytes of flotsom and jetsum of the Ericsson and Nokia software packages.

 

 

 

In short unless your computer's operating system is newer than the phone you probably will need a modem driver specific to your phone so the computer recognizes your phone as a modem. The manufacture likely has a software suite that helps you keep in sync with MS Outlook's address book as well as some other novelty features. However if all you want is the modem driver try to get help from a users group

[Guest]

Cheers! I suspect I have another problem in that my phone which is a 6110 not a 6210 needs to be replaced. Dont think it has a built in modem.

 

 

 

Is there any way one can use this phone with a pcm card modem?

 

 

 

I lost you on most of the stuff about GPRS but what I did pick up is that this is new technology which I assume is only available on the latest phones and that uploads are slow.

 

 

 

What is the advantage of this medium over the conventional technology?

 

 

 

Most people I have spoken to dont like IR and recomend that I use a cable connector. Is the problem with IR user related or does it have its moments.

 

 

 

 

[adikgede]

re GPRS

 

 

 

If you use if you use your phone as a modem dialing to a traditional ISP (GSM 2.0) you get 9.6BKbs and you pay flat rate air time even if your ISP can't fill 9.6Kbs of bandwidth (all too often true in Indonesia)

 

 

 

If you use GPRS (GSM 2.5) you get 115Kbs (in theory) and you pay for the data you pass through the connection, not a flat rate. I don't know of any phones that will work at 115Kbs mine is rated at ~43Kbs and my wifes Nokia about 49Kbs. I have gotten data rates aproaching the specs but since GPRS is being offered free by my carrier at the moment traffic is often at a stand still. I can almost always read yahoo mail with my phone even if the I can't get any traffic across a PC.

 

 

 

With many Nokia phones there is not such a thing as a serial cable so IR is all you got. I have never had any problems with IR but my wife always puts her hand over the IR port when she is reading something.