Hayes command compatible cell phones?

[Dave]

The Motorola c168i is a Hayes compatible cell phone, but it was
introduced in '05 and is somewhat dated and it's hard to find a new
one (most are used). Are there any more recent/modern cell phones
that are Hayes command (aka AT command) compatible? I plan on using
this with a microcontroller, so a USB connection is out.

Thanks!
Dave

[John Henderson]

Post by Dave
The Motorola c168i is a Hayes compatible cell phone, but it was
introduced in '05 and is somewhat dated and it's hard to find a new
one (most are used). Are there any more recent/modern cell phones
that are Hayes command (aka AT command) compatible? I plan on using
this with a microcontroller, so a USB connection is out.

Does it need to be a phone? Or will a cellular modem do?

What tasks will the device be performing under microprocessor
control?

The advantages of a modem include its greater likelihood of
having an RS232 serial interface, and its being powered
directly from a low voltage DC source. It will also support a
rich set of "AT" commands, including the cellular extensions
(generally beginning "AT+C").

If you need a phone, look for a cheap one - not a smart phone
with a sophisticated cellular operating system like Symbian
which will "protect" you from having to interface directly with
standard "AT" commands.

What wireless technology should it support? I presume GSM by
your choice of newsgroups, but 2GSM or 3GSM (UMTS)?

John

[Dave]

Post by Dave
The Motorola c168i is a Hayes compatible cell phone, but it was
introduced in '05 and is somewhat dated and it's hard to find a new
one (most are used).  Are there any more recent/modern cell phones
that are Hayes command (aka AT command) compatible?  I plan on using
this with a microcontroller, so a USB connection is out.

Does it need to be a phone?  Or will a cellular modem do?
What tasks will the device be performing under microprocessor
control?
The advantages of a modem include its greater likelihood of
having an RS232 serial interface, and its being powered
directly from a low voltage DC source. It will also support a
rich set of "AT" commands, including the cellular extensions
(generally beginning "AT+C").
If you need a phone, look for a cheap one - not a smart phone
with a sophisticated cellular operating system like Symbian
which will "protect" you from having to interface directly with
standard "AT" commands.
What wireless technology should it support?  I presume GSM by
your choice of newsgroups, but 2GSM or 3GSM (UMTS)?
John

I'm open to a cellular modem, but I will be using it for SMS messaging
only (used to relay GPS data and read commands from incoming
messages), so I don't need high bandwidth. I was leaning towards
phone due to price, although I'm not sure which ones support "AT"
commands other than the c168i, which is becoming obsolete.

Thanks,
Dave

[John Henderson]

Post by Dave
I'm open to a cellular modem, but I will be using it for SMS messaging
only (used to relay GPS data and read commands from incoming
messages), so I don't need high bandwidth. I was leaning towards
phone due to price, although I'm not sure which ones support "AT"
commands other than the c168i, which is becoming obsolete.

You may find the modem cheaper in the long run, as they don't
have an internal battery which is the usual failure point in a
phone.

Looking at the Motorola c168i, I guess you're in North America
and want an 850/1900 MHz GSM device.

If you were elsewhere, I could post you an old but unused and
unwanted Falcom 900/1800 MHz modem gratis. I was given a couple
of these once, and the only idiosyncrasy I've found is that the
"AT" command syntax is upper case (except the lower case command
arguments which are permissible in GSM 07.05 and 07.07). You'd
need a basic external antenna for such an older modem.

As a matter of interest, are you using text-mode or PDU-mode for
your SMSs?

John

[John Henderson]

Post by John Henderson
As a matter of interest, are you using text-mode or PDU-mode for
your SMSs?

You're likely already aware of this, but the main reason I ask is
that the answer may be crucial to your choice of phone. If
there's only "0" and no "1" in the response to the "AT+CMGF=?"
command, a new phone will be a PDU-mode only device (as many
phones are).

This means that you'll need to have coded the complex algorithm
to prepare the SMS as Protocol Data Units (PDUs) instead of
relying on the phone to do the conversion from text for you.
Such code may go well beyond the memory capacity of a simple
microcontroller.

John

[Dave]

Post by John Henderson

Post by John Henderson
As a matter of interest, are you using text-mode or PDU-mode for
your SMSs?

You're likely already aware of this, but the main reason I ask is
that the answer may be crucial to your choice ofphone. If
there's only "0" and no "1" in the response to the "AT+CMGF=?"
command, a newphonewill be a PDU-mode only device (as many
phones are).
This means that you'll need to have coded the complex algorithm
to prepare the SMS as Protocol Data Units (PDUs) instead of
relying on thephoneto do the conversion from text for you.
Such code may go well beyond the memory capacity of a simple
microcontroller.
John

I'm really only looking to send text (location and some data), and am
not aware of the difference between PDU-mode and text-mode. How do I
tailor my choices to text-mode compatible phones?

As a second follow-up, the Motorola c168i can interface through the
mic jack. I assume this is an exception, and most phone require using
RX and TX pins on the connector...? If that's the case, that also
eliminates phones that use USB connections since I doubt I'll be able
to emulate a USB controller with a PIC...?

Thanks for the advice!
Dave

[John Henderson]

Post by Dave
I'm really only looking to send text (location and some data), and am
not aware of the difference between PDU-mode and text-mode. How do I
tailor my choices to text-mode compatible phones?

You'd need to check the specification, or ask. Failing that,
you can test a phone interactively by issuing the query form of
the message format command from GSM 07.05, like this:

AT+CMGF=?

+CMGF: (0-1)

OK

In this case, the zero in the "+CMGF: (0-1)" response means that
PDU-mode is supported, while the one means text-mode is
supported.

The question to ask is whether the phone supports text-mode from
GSM technical spec 07.05 (not that sales people are likely to
know, let alone understand the question).

Text-mode enables you to simply give the modem the text you want
to send. With PDU-mode, you must effectively break each message
character into bits and reassemble those bits packed in a
specific sequence as per section 6.1.2.1.1 of GSM 03.38.

Post by Dave
As a second follow-up, the Motorola c168i can interface through the
mic jack. I assume this is an exception, and most phone require using
RX and TX pins on the connector...? If that's the case, that also
eliminates phones that use USB connections since I doubt I'll be able
to emulate a USB controller with a PIC...?

I can't confirm with any certainty, but what you say sounds right.

Phones with old RS232 type TX and RX connectors would be very
rare these days.

John

[Dave]

Post by Dave
I'm really only looking to send text (location and some data), and am
not aware of the difference between PDU-mode and text-mode.  How do I
tailor my choices to text-mode compatible phones?

You'd need to check the specification, or ask.  Failing that,
you can test a phone interactively by issuing the query form of
        AT+CMGF=?
        +CMGF: (0-1)
        OK
In this case, the zero in the "+CMGF: (0-1)" response means that
PDU-mode is supported, while the one means text-mode is
supported.
The question to ask is whether the phone supports text-mode from
GSM technical spec 07.05 (not that sales people are likely to
know, let alone understand the question).
Text-mode enables you to simply give the modem the text you want
to send.  With PDU-mode, you must effectively break each message
character into bits and reassemble those bits packed in a
specific sequence as per section 6.1.2.1.1 of GSM 03.38.

Post by Dave
As a second follow-up, the Motorola c168i can interface through the
mic jack.  I assume this is an exception, and most phone require using
RX and TX pins on the connector...?  If that's the case, that also
eliminates phones that use USB connections since I doubt I'll be able
to emulate a USB controller with a PIC...?

I can't confirm with any certainty, but what you say sounds right.
Phones with old RS232 type TX and RX connectors would be very
rare these days.
John

Great, thanks for the info! I do have 2 follow-up questions if you
don't mind... When you say RS232 type TX and RX connectors on a phone
are rare, are you referring to the voltage levels? I assume I can
communicate with most cell phones with TTL?

Secondly, if I connect a cell phone to my PC and correctly configure
the baud rate, parity, etc... and query it with "AT+CMGF=?", will most
cell phones respond with its PDU-mode and text-mode capabilities? I
guess what I'm asking is do most cell phones still actually respond to
AT commands, or is that going the way of the Dodo?

Thanks again John!
Dave

[John Henderson]

Post by Dave
Great, thanks for the info! I do have 2 follow-up questions if you
don't mind... When you say RS232 type TX and RX connectors on a phone
are rare, are you referring to the voltage levels? I assume I can
communicate with most cell phones with TTL?

My experience with controlling phones via a PC's standard RS232
serial port has been limited to using a serial adaptor cable
supplied by the phone manufacturer.

These days, I generally use a USB cable (modern USB modems with
built-in antenna) or Bluetooth (modern phones).

Post by Dave
Secondly, if I connect a cell phone to my PC and correctly configure
the baud rate, parity, etc... and query it with "AT+CMGF=?", will most
cell phones respond with its PDU-mode and text-mode capabilities? I
guess what I'm asking is do most cell phones still actually respond to
AT commands, or is that going the way of the Dodo?

Cheaper phones still seem to support "AT" commands. More
expensive "smart phones" don't seem to.

John

[John Henderson]

Post by Dave
Secondly, if I connect a cell phone to my PC and correctly configure
the baud rate, parity, etc... and query it with "AT+CMGF=?", will most
cell phones respond with its PDU-mode and text-mode capabilities?

On that specific point, I'd expect a phone claiming compliance
with GSM 07.05 to support the "AT+CMGF=?" command. And the
slightly different syntax "AT+CMGF?" (no "=") to tell you which
setting is currently active. As per this dialog:

AT+CMGF?

+CMGF: 0

OK
AT+CMGF=?

+CMGF: (0-1)

OK
AT+CMGF=1

OK
AT+CMGF?

+CMGF: 1

OK

If a phone supports "AT" commands in general, the command to list
all supported "AT" commands is:

AT+CLAC

See GSM 07.07.

John

[tlvp]

Post by Dave

Post by John Henderson

Post by Dave
The Motorola c168i is a Hayes compatible cell phone, but it was
introduced in '05 and is somewhat dated and it's hard to find a new
one (most are used). Are there any more recent/modern cell phones
that are Hayes command (aka AT command) compatible? I plan on using
this with a microcontroller, so a USB connection is out.

Does it need to be a phone? Or will a cellular modem do?
What tasks will the device be performing under microprocessor
control?
The advantages of a modem include its greater likelihood of
having an RS232 serial interface, and its being powered
directly from a low voltage DC source. It will also support a
rich set of "AT" commands, including the cellular extensions
(generally beginning "AT+C").
If you need a phone, look for a cheap one - not a smart phone
with a sophisticated cellular operating system like Symbian
which will "protect" you from having to interface directly with
standard "AT" commands.
What wireless technology should it support? I presume GSM by
your choice of newsgroups, but 2GSM or 3GSM (UMTS)?
John

I'm open to a cellular modem, but I will be using it for SMS messaging
only (used to relay GPS data and read commands from incoming
messages), so I don't need high bandwidth. I was leaning towards
phone due to price, although I'm not sure which ones support "AT"
commands other than the c168i, which is becoming obsolete.
Thanks,
Dave

One handset that will do what you want is the obsolescent Motorola TimePort
P-280, a 3-band GSM handset with a standard adapter cable available from the
connector on the base of the phone to a standard 9-pin RS-232 serial connector.

Any standard RS-232 serial output port on any PC will communicate thru' it,
even that on my equally old Palm IIIe (which for a long time used to connect
me to MCI Mail through that handset in that way).

HTH. Cheers, -- tlvp

[R. Mark Clayton]

Post by Dave
The Motorola c168i is a Hayes compatible cell phone, but it was
introduced in '05 and is somewhat dated and it's hard to find a new
one (most are used). Are there any more recent/modern cell phones
that are Hayes command (aka AT command) compatible?

Dunno, but lots of Motorola phones supported Hayes command set e.g. over
iRDA.

Post by Dave
I plan on using this with a microcontroller, so a USB connection is out.

Er why so - you can get a microcontroller on a USB dongle for evaluation:for
about $25 - Google up.

Post by Dave
Thanks!
Dave

[Dave]

Post by R. Mark Clayton

Post by Dave
The Motorola c168i is a Hayes compatible cell phone, but it was
introduced in '05 and is somewhat dated and it's hard to find a new
one (most are used).  Are there any more recent/modern cell phones
that are Hayes command (aka AT command) compatible?

Dunno, but lots of Motorola phones supported Hayes command set e.g. over
iRDA.

Post by Dave
I plan on using this with a microcontroller, so a USB connection is out.

Er why so - you can get a microcontroller on a USB dongle for evaluation:for
about $25 - Google up.

Post by Dave
Thanks!
Dave

I think most of the microcontrollers with USB connections are slave
devices that are programmed via USB. To control the phone, the
microcontroller would have to emulate a USB master device, and
emulating a USB master device with a standard PIC would be tough...
I'm sure I could use a specialized chip or figure out some way to use
a USB phone, but at this point I think it'd be easier to just use a
phone that has an easy connection.

Thanks though!
Dave

[John Henderson]

Post by Dave
The Motorola c168i is a Hayes compatible cell phone, but it was
introduced in '05 and is somewhat dated and it's hard to find a new
one (most are used). Are there any more recent/modern cell phones
that are Hayes command (aka AT command) compatible? I plan on using
this with a microcontroller, so a USB connection is out.

I've discussed using a modem as an alternative. But a module
might be a far better option for your application. This is the
first example which came up on my search:

http://www.gsm-modem.de/gsm-module.html

John