Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

wrote:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!

Ah ! Is that what it is ? I installed one of those too and wondered what the
trouble is. If you're quick I could get it to dial out but it never dropped the
line after connecting.

Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

Who did you buy yours from ? Why are they selling something that doesn't work ?

Have you got as far as drawing a circuit ? I hadn't gone any further with mine
since it's not very urgent.

Graham

Pooh Bear wrote:
wrote:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!

Ah ! Is that what it is ? I installed one of those too and wondered what the
trouble is. If you're quick I could get it to dial out but it never dropped the
line after connecting.

Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

Who did you buy yours from ? Why are they selling something that doesn't work ?

Have you got as far as drawing a circuit ? I hadn't gone any further with mine
since it's not very urgent.

Graham

Nope and I doubt I will be able -it's just too tiny!

On 19 Jun 2006 08:44:34 -0700, wrote:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

That sounds weird/unbelievable. Check on-line to see if there's a
firmware update or perhaps an AT command that will change its
behavior?

I'm assuming it is new and just behaves this way and didn't go bad . .
.. The fact that you see that delay seems to suggest it may be working
but just a command/software problem - also if there's a pass-through
jack for the telephone make sure the line goes into the correct jack.

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

Once you disconnect the line and plug it back in, it goes free for
few moments...

The symptom you are describing is that of stuck contacts in the hook
relay. But then you say that there is none ...

What do you suggest I check, other than the optocoupler?

The optocoupler is there to detect the ring voltage and to isolate it
from the host side electronics. There should be a 1uF 250V cap in
series with its input, as well as a ~10K resistor.

( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

There has to be some way for the host side electronics to control the
off-hook/on-hook state of the DAA. Look for a hook relay, possibly
solid state. Otherwise look for any device that bridges the gap
between the host and line sides.

Can you upload a photo to your web space?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

One thing to check is whether the modem grabs the line when the PC is
powered down. If not, then this would point to a problem on the host
side.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Franc Zabkar wrote:

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

The one I have has no relay or transformer.

I'm seeing 19M across the line on the bare pcb.

I'll look further.

It has some approvals logos printed on it but I guess they could be fraudulent.

Graham

My guess is that you're running into the same problem that I originally
had with my USR 56K Fax modem, until I learned how to set its switches.
The problem that I ran into with the SM56 is that the Motorola website
evidently lacks the documentation telling you where to set the switches
for the configuration that you need, plus how to set them. All that I
could find on the SM56 at the Motorola website was a few pages of PR
and advertising, without any technical detail.

I seriously doubt that the SM56 hardware is at fault, but their
published documentation is certainly wanting of more detailed technical
instructions.

I'd suggest that you email Motorola about this problem.

Harry C.


wrote:
Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

wrote:

}Looked at several Motorola SM56 modems an all have the same fault-non
}infinite resistance at line jack...

Non-infinite resistance when un-installed (i.e. not in the PC)? Or does it
go non-infinite only when installed & pc powered on?

Stan.

On 2006-06-19, Pooh Bear wrote:


Franc Zabkar wrote:

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

The one I have has no relay or transformer.

I'm seeing 19M across the line on the bare pcb.

At 48V ?

Bye.
Jasen

On Tue, 20 Jun 2006 00:48:22 +0100, Pooh Bear
put finger to keyboard and
composed:



Franc Zabkar wrote:

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

The one I have has no relay or transformer.

I'm seeing 19M across the line on the bare pcb.

You might be looking into a diode bridge, either discrete or internal
to a line side chip.

I'd be checking whether the modem goes off-hook when the PC is powered
down. If not, then your line side electronics is probably OK. Next I
would check whether the modem grabs the line during the POST, ie
before its drivers have a chance to load.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On 19 Jun 2006 21:34:10 -0700, put finger to keyboard
and composed:

My guess is that you're running into the same problem that I originally
had with my USR 56K Fax modem, until I learned how to set its switches.
The problem that I ran into with the SM56 is that the Motorola website
evidently lacks the documentation telling you where to set the switches

That's because there are none. The SM56 is an internal (S)oft(M)odem.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On 20 Jun 2006 17:26:02 -0700, put finger to keyboard
and composed:

Franc, the USR 56K Faxmodem is also an internal soft modem (new
word?).

Modems are classified as "soft", controllerless, or "hard". The former
has a DAA and not much else, the second has a DAA + DSP, and the
latter has a DAA + DSP + controller. If any functional block is
missing, then it is emulated by a driver. Softmodems are technically
the worst because they rely on the host CPU to do everything. That is
not to say that softmodems are necessarily bad.

All of today's modems have setup switch settings, either hard or soft.

Some external USR modems, eg Courier, had a physical bank of switches.
I thought you were referring to them.

Without these the modem would be relatively inflexible and useless.
It's usually the modem initialization control command that sets them
up, and they typically run from S1 to S7 or more. These determine such
basic things such as if the modem is on-line continuously, normally
off-line, auto-answer, automatic retries, etc. You need to have a copy
of the chipset producer's technical data sheet to learn how to use
them, without which the chipset is virtually useless.

I know of no S-register that would cause a modem to power up in an
off-hook state, nor any reason why you would want it to. If the
software or the modem's driver is commanding it to go off-hook, then
something is very wrong. Having said that, I seem to recall some
Conexant modems that would not release the line after disconnection.
The fix was a driver update.

If you are a Windows user, your modemlog file will tell you which
commands are being sent to your modem, and how the modem is
responding.

Without knowledge of what these settings mean and how to use them,
you're simply flying blind. This is why you need the data sheet.

An ATZ command will reset the modem and an ATH will hang it up. Both
commands are normally sent by DUN in the course of a dial-up session.
I'd suggest that the OP launch a HyperTerminal comms session and send
an ATE1M2L3 command (to enable command echo and turn on the speaker at
max volume) and then send an ATH1 to take the modem off-hook and an
ATH to hang it up. Monitor the voltage at the wall outlet while doing
this. The on-hook voltage should be about 50V and the off-hook volts
should drop to around 10V-20V.

It may also be interesting to see whether the modem is able to pulse
dial, eg ATDP12345678, as this relies on interrupting the loop current
via the hook switch.

When you purchase an integrated system, the system designers have
already done this basic bit of homework for you.

The factory settings are restored by an AT&F command.

But if you're starting
with the raw chipset, you have to do this bit of research for youself.

Harry C.

I found these documents useful:

"Software Modem and Audio/Modem Riser (AMR) Design"
http://www.eetasia.com/ARTICLES/1999...TEK_CT_TAC.PDF

Modem user manual with a chapter on SM56 AT commands:
http://www.modem-help.freeserve.co.u...la_sm56pci.pdf

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On 6/20/06 1:48 AM, in article net, "jasen"
wrote:

On 2006-06-19, Pooh Bear wrote:


Franc Zabkar wrote:

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

The one I have has no relay or transformer.

I'm seeing 19M across the line on the bare pcb.

At 48V ?

Bye.
Jasen

I'm late getting into this, but.....

Have you looked at the documentation for the modem? As a condition of the
Registration program in the U.S., the manufacturer must declare the Ringer
Equivalence for the modem. There are two ways to determine the Ringer
Equivalence Number (REN), and one of them is the Tip to Ring dc resistance.
If they declare REN=2 then the 19M you see may be normal, and is probably
not your problem.

Don

Franc, the USR 56K Faxmodem is also an internal soft modem (new
word?).

All of today's modems have setup switch settings, either hard or soft.
Without these the modem would be relatively inflexible and useless.
It's usually the modem initialization control command that sets them
up, and they typically run from S1 to S7 or more. These determine such
basic things such as if the modem is on-line continuously, normally
off-line, auto-answer, automatic retries, etc. You need to have a copy
of the chipset producer's technical data sheet to learn how to use
them, without which the chipset is virtually useless.

Without knowledge of what these settings mean and how to use them,
you're simply flying blind. This is why you need the data sheet.

When you purchase an integrated system, the system designers have
already done this basic bit of homework for you. But if you're starting
with the raw chipset, you have to do this bit of research for youself.

Harry C.



Franc Zabkar wrote:
On 19 Jun 2006 21:34:10 -0700, put finger to keyboard
and composed:

My guess is that you're running into the same problem that I originally
had with my USR 56K Fax modem, until I learned how to set its switches.
The problem that I ran into with the SM56 is that the Motorola website
evidently lacks the documentation telling you where to set the switches

That's because there are none. The SM56 is an internal (S)oft(M)odem.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

What switch settings are you using in your initialization command?

Realize that these are very similar from modem to modem, but not
usually identical. You really need the data sheets for the SM56, which
unfortunately I couldn't find on Motorola's website for some strange
reason.

Harry C.



wrote:
Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

Just as an afterthought, Motorola does have some downloadable SM56
drivers on their website. It's quite possible that these will do the
modem setup for you....and certainly worth a try.

Harry C.


wrote:
Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

Don Bowey wrote:

On 6/20/06 1:48 AM, in article net, "jasen"
wrote:

On 2006-06-19, Pooh Bear wrote:


Franc Zabkar wrote:

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

The one I have has no relay or transformer.

I'm seeing 19M across the line on the bare pcb.

At 48V ?

Bye.
Jasen

I'm late getting into this, but.....

Have you looked at the documentation for the modem? As a condition of the
Registration program in the U.S., the manufacturer must declare the Ringer
Equivalence for the modem. There are two ways to determine the Ringer
Equivalence Number (REN), and one of them is the Tip to Ring dc resistance.
If they declare REN=2 then the 19M you see may be normal, and is probably
not your problem.

The box contains a driver CD, a leaflet like 'manual' with none of that info, a
piece of foam plastic and the pcb in an anti-static bag.

The pcb has TUV, CE and FCC ( but not an FCC id ) printed on it together with
what I originally took to be the BABT approvals symbol ( but possibly isn't ).

I suspect the above are bogus.

There's no manufacturers info anywhere but I recall that it was sold as 'Mentor'
brand.

I've an idea to report this. Maybe I'll give the company that sold it a chance
to replace it though ?

Graham

Franc Zabkar wrote:

On Tue, 20 Jun 2006 00:48:22 +0100, Pooh Bear
put finger to keyboard and
composed:

Franc Zabkar wrote:

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

The one I have has no relay or transformer.

I'm seeing 19M across the line on the bare pcb.

You might be looking into a diode bridge, either discrete or internal
to a line side chip.

There's a WO series 1 amp bridge on the line.


I'd be checking whether the modem goes off-hook when the PC is powered
down. If not, then your line side electronics is probably OK. Next I
would check whether the modem grabs the line during the POST, ie
before its drivers have a chance to load.

I'll check that when I get a sec.

Graham

wrote:

Franc, the USR 56K Faxmodem is also an internal soft modem (new
word?).

All of today's modems have setup switch settings, either hard or soft.
Without these the modem would be relatively inflexible and useless.
It's usually the modem initialization control command that sets them
up, and they typically run from S1 to S7 or more. These determine such
basic things such as if the modem is on-line continuously, normally
off-line, auto-answer, automatic retries, etc. You need to have a copy
of the chipset producer's technical data sheet to learn how to use
them, without which the chipset is virtually useless.

Without knowledge of what these settings mean and how to use them,
you're simply flying blind. This is why you need the data sheet.

When you purchase an integrated system, the system designers have
already done this basic bit of homework for you. But if you're starting
with the raw chipset, you have to do this bit of research for youself.

Eh ? My SM56 was sold to me as a retail PCI modem.

Motorola no longer make that chip anyway and indeed Motorola's not into selling
semis at all any more ( it's On Semi and Waferscale ? now )

Graham

On 6/20/06 6:04 PM, in article , "Pooh Bear"
wrote:



Don Bowey wrote:

On 6/20/06 1:48 AM, in article net, "jasen"
wrote:

On 2006-06-19, Pooh Bear wrote:


Franc Zabkar wrote:

On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

The one I have has no relay or transformer.

I'm seeing 19M across the line on the bare pcb.

At 48V ?

Bye.
Jasen

I'm late getting into this, but.....

Have you looked at the documentation for the modem? As a condition of the
Registration program in the U.S., the manufacturer must declare the Ringer
Equivalence for the modem. There are two ways to determine the Ringer
Equivalence Number (REN), and one of them is the Tip to Ring dc resistance.
If they declare REN=2 then the 19M you see may be normal, and is probably
not your problem.

The box contains a driver CD, a leaflet like 'manual' with none of that info,
a
piece of foam plastic and the pcb in an anti-static bag.

The pcb has TUV, CE and FCC ( but not an FCC id ) printed on it together with
what I originally took to be the BABT approvals symbol ( but possibly isn't ).

I suspect the above are bogus.

There's no manufacturers info anywhere but I recall that it was sold as
'Mentor'
brand.

I've an idea to report this. Maybe I'll give the company that sold it a chance
to replace it though ?

Graham


Even a soft-modem needs hardware. For example, my new HP computer has a
soft-modem and it works through a PCI card, and it is called a PCI
soft-modem. Among other things, it has the RJ11 physical connection to the
phone line. It is this PCI card that will have the REN and other FCC
required info.

I imagine some motherboards could have this functionality so that a PCI card
isn't needed, but whether it's a PCI card, or it's on the computer
motherboard, it must contain all FCC Part 68 and Part 15 info, or it won't
be in compliance with Federal Law.

If it will help, tomorrow I will pull the PCI card and see what info it
provides.

What are you using for a terminal program?

Don

wrote:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)
There is a diode bridge so the line interface is a 'dry transformer'
type.Once you disconnect the line and plug it back in, it goes free for
few moments...
What do you suggest I check, other than the optocoupler?( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

hmm, maybe your line in your home is wired backwards and
the modem thinks it should be on line?
its been so long since i have even used a modem when DSL
came out.


--
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

Franc Zabkar wrote:
On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

Once you disconnect the line and plug it back in, it goes free for
few moments...

The symptom you are describing is that of stuck contacts in the hook
relay. But then you say that there is none ...

What do you suggest I check, other than the optocoupler?

The optocoupler is there to detect the ring voltage and to isolate it
from the host side electronics. There should be a 1uF 250V cap in
series with its input, as well as a ~10K resistor.

( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

There has to be some way for the host side electronics to control the
off-hook/on-hook state of the DAA. Look for a hook relay, possibly
solid state. Otherwise look for any device that bridges the gap
between the host and line sides.

Can you upload a photo to your web space?

- Franc Zabkar
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Please remove one 'i' from my address when replying by email.

here are the photos
http://putfile.com/pic.php?pic=6/17113372064.jpg&s=x2
http://putfile.com/pic.php?pic=6/17113412857.jpg&s=x2

the big lower left transistor is equiv of 2n5550 so I guess replaces
the box relay,
I wonder if somehow it could be replaced with it

Don Bowey wrote:

Even a soft-modem needs hardware.

Yes, I have this PCI card that's based on a Motorola 'SM56' Chip.


For example, my new HP computer has a
soft-modem and it works through a PCI card, and it is called a PCI
soft-modem. Among other things, it has the RJ11 physical connection to the
phone line. It is this PCI card that will have the REN and other FCC
required info.

It *should* have yes.


I imagine some motherboards could have this functionality so that a PCI card
isn't needed,

Correct but this isn't the case here. I've had an integrated mobo like that in the
past and it worked fine. This issue relates to a PCI card.


but whether it's a PCI card, or it's on the computer
motherboard, it must contain all FCC Part 68 and Part 15 info, or it won't
be in compliance with Federal Law.

Federal Law doesn't count for much in the UK. We have our own laws.


If it will help, tomorrow I will pull the PCI card and see what info it
provides.

What are you using for a terminal program?

I haven't used the terminal program in ages !

I want to use it for a dial-up PPP account to an ISP !

Graham

On Tue, 20 Jun 2006 19:06:46 -0700, Don Bowey put
finger to keyboard and composed:

Even a soft-modem needs hardware. For example, my new HP computer has a
soft-modem and it works through a PCI card, and it is called a PCI
soft-modem. Among other things, it has the RJ11 physical connection to the
phone line. It is this PCI card that will have the REN and other FCC
required info.

I imagine some motherboards could have this functionality so that a PCI card
isn't needed, but whether it's a PCI card, or it's on the computer
motherboard, it must contain all FCC Part 68 and Part 15 info, or it won't
be in compliance with Federal Law.

I don't think you will ever find a desktop motherboard with all the
modem bits on it. This is because each jurisdiction has its own
telecom authority with its own specific requirements. Imagine if each
and every motherboard had to undergo telecom compliance testing in
every country in the world.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Franc Zabkar wrote:

On Thu, 22 Jun 2006 02:51:16 +0100, Arthur Dent
put finger to keyboard and
composed:

What are you using for a terminal program?

I haven't used the terminal program in ages !

I want to use it for a dial-up PPP account to an ISP !

Graham

A terminal program (eg HyperTerminal) is useful for troubleshooting
purposes. For example, most modems respond to diagnostic commands such
as AT#UD, AT&V1, AT&V2, AT#UG, and quite a few others. I believe the
SM56 is quite good in this regard.

Good point. Once upon a time I even knew a few Hayes commands.

Graham

Franc Zabkar је напиÑ?ао
On 21 Jun 2006 12:04:18 -0700, put finger to
keyboard and composed:


Franc Zabkar wrote:
On 19 Jun 2006 08:44:34 -0700, put finger to
keyboard and composed:

Looked at several Motorola SM56 modems an all have the same fault-non
infinite resistance at line jack which causes them to take over the
line once the line is plugged, so none of the telephones can be used!
Checked the MOV and it is ok and there is no relay on modem !(at least
not a box type, just few too many smd transistors doing smth?)

There is a diode bridge so the line interface is a 'dry transformer'
type.

If there is a transformer, then the DAA is probably dry, as you say.
Otherwise there would usually be two chips, one on the line side and
one on the host side, with two or three ceramic caps providing the
isolation.

Once you disconnect the line and plug it back in, it goes free for
few moments...

The symptom you are describing is that of stuck contacts in the hook
relay. But then you say that there is none ...

What do you suggest I check, other than the optocoupler?

The optocoupler is there to detect the ring voltage and to isolate it
from the host side electronics. There should be a 1uF 250V cap in
series with its input, as well as a ~10K resistor.

( because I
think it has to be ok since the modem is actually working if I manage
to hook to provider in few seconds before it takes over the line)

There has to be some way for the host side electronics to control the
off-hook/on-hook state of the DAA. Look for a hook relay, possibly
solid state. Otherwise look for any device that bridges the gap
between the host and line sides.

Can you upload a photo to your web space?

- Franc Zabkar

here are the photos
http://putfile.com/pic.php?pic=6/17113372064.jpg&s=x2
http://putfile.com/pic.php?pic=6/17113412857.jpg&s=x2

the big lower left transistor is equiv of 2n5550 so I guess replaces
the box relay,
I wonder if somehow it could be replaced with it

It appears that you may have a "Kobian Mercury HPI56MII Data/Fax PCI"
modem:
http://www.modem-help.co.uk/mfc/kobian.html#hpi56mii

The two 16-pin chips, and/or possibly the 14-pin chip, appear to be
the line side and host side pair/trio of a silicon DAA. The two
ceramic caps provide the data path and isolation barrier. There is a
protective gap in the PCB underneath them. The line side IC would
incorporate the function of the hook relay and signal transformer. The
host side IC would, among other things, provide the off-hook/on-hook
control signals. In many conventional transformer-based modems, the
loop current passes through, and is stabilised by, a Darlington
transistor. This may be the function of the 2N5550 (???)
thanks for taking a look
One confirmation the chips you mention- mot6269352/4 are making up the
DAA
is the diode attached to its pins probably as flyback for the internal
relay.
I doubt the diode bridge is relevant since it should be located behind
the relay in front of (incorporated) transformer. The resistance at
modems line jack is few Kohms(Varistor desoldered) either right away or
in case of several other modems only after the modem(out of the PC)
grabs the line! ATZ/ATH/ATH1 report ok but do not release the line. I
guess somehow smth energizes the relay .. - Franc Zabkar
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