Interface from telephone to computer - options?
Eusebius
coaching calls. So I want to use a binaural headset and microphone. I
could get a seperate headset like the Plantronics ones, but it seems
to me that I could just link the telephone to my Mac computer and
listen and record (I'd like to record too) etc from the computer,
using the headset and microphone I use for Skype already.
Do I need an interface, or is the line in and line out to the
telephone just normal 2 volts type line level? In other words I could
make a DIY interconnect with just phono plugs for the computer line in/
line out sockets?
All help welcome for this. I can solder connections and am handy with
sound equipment.
andy
Dave Plowman (News)
<04f3ae9d-d0c1-4229...@z41g2000yqz.googlegroups.com>,
> andy
I have a dial-up modem which takes a headset and has software for dialling
out or accepting ordinary voice incoming calls. That would seem to be your
easiest way. However, the quality is restricted by the bandwidth of a
telephone circuit. If you want better quality this can be done with a
broadband connection.
--
*It was all so different before everything changed.
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
Guy Dawson
> Do I need an interface,
Yes.
> or is the line in and line out to the telephone just normal 2 volts
> type line level?
No. There's usually about 50v DC between the pair of wires that come
into your house.
For Windows and Linux systems Dialogic do a large range of interface
cards including two port analogue ones. I don't think there's much
there for Macs though.
Guy
-- ---------------------------------------------------------------------
Guy Dawson@SMTP - gn...@cuillin.org.uk // ICBM - 6.15.16W 57.12.23N 986M
4.4>5.4 4.4>5.4 4.4>5.4 The Reality Check's in the Post! 4.4>5.4 4.4>5.4
John Weston
@z41g2000yqz.googlegroups.com>, "Eusebius" wrote:
>
> I want high quality sound from the telephone for making long distance
> coaching calls. So I want to use a binaural headset and microphone. I
> could get a seperate headset like the Plantronics ones, but it seems
> to me that I could just link the telephone to my Mac computer and
> listen and record (I'd like to record too) etc from the computer,
> using the headset and microphone I use for Skype already.
>
> Do I need an interface, or is the line in and line out to the
> telephone just normal 2 volts type line level? In other words I could
> make a DIY interconnect with just phono plugs for the computer line in/
> line out sockets?
Phone lines aren't the same as "line input"
Don't do what you are apparently thinking of doing. You will ground one
side of the balanced phone circuit and this will bring up a ground fault
alarm in the exchange, which may or may not generate a fault call for
which you could be charged. You need to use an isolation transformer,
such as those available from Maplin, etc. e.g.
http://www.maplin.co.uk/Module.aspx?ModuleNo=30352, etc.
Better to get a phone with an inbuilt headset adaptor such as the
Plantronics ones you have found.
--
John W
I you want to mail me, replace the obvious with co.uk twice
Andy Burns
> For Windows and Linux systems Dialogic do a large range of interface
> cards including two port analogue ones. I don't think there's much
> there for Macs though.
Use a voice modem, with whatever headset you already have on the
machine, I dunno what software exists for this purpose on a Mac though.
d...@gglz.com
outs, no crackles, no delays - you need ISDN.
I had it for a while when broadband was unavailable here (home
highway), data rate nothing special (but reliable and near-instant
connection) - but voice calls connect (as afar as you can tell)
instantly, with an "in the same room" quality if it's end to end ISDN,
and pretty good if it's ISDN to analogue. You also get 3 different
numbers you can use, which may be useful.
Not a cheap solution, but if this is the basis of your business, then
the additional cost might be trivial to you. However you would need a
dedicated line - you can't have IDSN and broadband on the same line.
fred
Weston <inv...@earlsway.invalid> writes
>
>Phone lines aren't the same as "line input"
>
>Don't do what you are apparently thinking of doing. You will ground one
>side of the balanced phone circuit and this will bring up a ground fault
>alarm in the exchange, which may or may not generate a fault call for
>which you could be charged. You need to use an isolation transformer,
>such as those available from Maplin, etc. e.g.
>http://www.maplin.co.uk/Module.aspx?ModuleNo=30352, etc.
>
outgoing levels (it connects to and requires a handset socket) which is
a good idea.
An off the shelf isolating transformer wont match the levels so they are
like to be imbalanced and of course wouldn't be approved for connection
to the telecom network.
>Better to get a phone with an inbuilt headset adaptor such as the
>Plantronics ones you have found.
>
Or a voice modem if driver support is available for the mac.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs
The Natural Philosopher
> It's now an older technology, but for super voice quality, no drop-
> outs, no crackles, no delays - you need ISDN.
>
> I had it for a while when broadband was unavailable here (home
> highway), data rate nothing special (but reliable and near-instant
> connection) - but voice calls connect (as afar as you can tell)
> instantly, with an "in the same room" quality if it's end to end ISDN,
> and pretty good if it's ISDN to analogue. You also get 3 different
> numbers you can use, which may be useful.
>
I've actually got a VOIP router to do my broadband, and second line out
from that to my PABX,. Apart from a slight delay in connection, its way
superior to my actual voice line, and with the gain turned way up,
louder too.
> Not a cheap solution, but if this is the basis of your business, then
> the additional cost might be trivial to you. However you would need a
> dedicated line - you can't have IDSN and broadband on the same line.
>
The answer is what I have done. It provides a second line at very keen
PAYG prices (no rental charge) at infinitely better quality.
For those interested, its a Billion Bipac 7404 VGP router - a bitch to
set up, but works very well and www.sipgate.co.uk provide the transfer
into the PSTN network.
I even get a number for it that is local to my exchange. That no one can
find as its ex just about every directory there is.
Owain
> To add, that one relies on the phone to balance the incoming and
> outgoing levels (it connects to and requires a handset socket) which is
> a good idea.
However a telephone will be adjusted to provide only sidetone to the
handset, not full level outgoing speech.
Really the best option is to use a proper studio type telephone
hybrid. If they still do it, the Canford reporter telephone would
probably be ideal (canford.co.uk part 98-037)
Otherwise it's a telephone balance unit eg
http://www.canford.co.uk/Browse/86809.aspx
Owain
Sidney Endon-Lee
You can, but not in the UK. Germany (Deutsche Telekom) intermixed the
two from the inception of ADSL. BT chose not to. It boils down to how
much low-end bandwidth the telecoms operator puts aside for either
analogue telephony or ISDN. In Germany, many lines were already ISDN,
so the ADSL roll-out had to take account of that. In the UK,
presumably, BT decided to do otherwise.
See http://en.kioskea.net/contents/technologies/adsl.php3
Sid
fred
<6fbcb282-4fac-44c4...@r24g2000yqd.googlegroups.com>,
Owain <spuorg...@gowanhill.com> writes
>On 20 Nov, 11:26, fred wrote:
>> To add, that one relies on the phone to balance the incoming and
>> outgoing levels (it connects to and requires a handset socket) which is
>> a good idea.
>
>However a telephone will be adjusted to provide only sidetone to the
>handset, not full level outgoing speech.
>
>Really the best option is to use a proper studio type telephone
>hybrid. If they still do it, the Canford reporter telephone would
>probably be ideal (canford.co.uk part 98-037)
>
>Otherwise it's a telephone balance unit eg
>http://www.canford.co.uk/Browse/86809.aspx
>
Voice i/f modem is beginning to sound easiest.
Andrew Gabriel
The Natural Philosopher <t...@invalid.invalid> writes:
> d...@gglz.com wrote:
>> It's now an older technology, but for super voice quality, no drop-
>> outs, no crackles, no delays - you need ISDN.
>>
>> I had it for a while when broadband was unavailable here (home
>> highway), data rate nothing special (but reliable and near-instant
>> connection) - but voice calls connect (as afar as you can tell)
>> instantly, with an "in the same room" quality if it's end to end ISDN,
>> and pretty good if it's ISDN to analogue. You also get 3 different
>> numbers you can use, which may be useful.
>>
>
> I've actually got a VOIP router to do my broadband, and second line out
> from that to my PABX,. Apart from a slight delay in connection, its way
> superior to my actual voice line, and with the gain turned way up,
> louder too.
4-5 years ago, I rolled out a private VoIP network across the
widespread family members, which we use when calling each other.
Just occasionally, someone's ADSL line will be down resulting in a
landline call. It's only then that you realise just how terrible
the landline is, compared to VoIP we've become used to.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Dave Plowman (News)
Andrew Gabriel <and...@cucumber.demon.co.uk> wrote:
> 4-5 years ago, I rolled out a private VoIP network across the
> widespread family members, which we use when calling each other.
> Just occasionally, someone's ADSL line will be down resulting in a
> landline call. It's only then that you realise just how terrible
> the landline is, compared to VoIP we've become used to.
An ordinary landline with good phones can give decent enough quality.
Trouble is people have got used to nasty mobile phones.
If you have a suitable computer prog try recording some speech off the
radio etc and chopping it into a 300 - 3000 Hz bandwidth. You might be
pleasantly surprised.
--
*Tell me to 'stuff it' - I'm a taxidermist.
Owain
> An ordinary landline with good phones can give decent enough quality.
> Trouble is people have got used to nasty mobile phones.
and nasty digital PBXen
Owain
Dave Liquorice
> It's now an older technology, but for super voice quality, no drop-
> outs, no crackles, no delays - you need ISDN.
No (noticeable) delays if you use ISDN to carry "3.1kHz audio" or
"Speech" but that is telephone quality. If the OP wants better than
that you'll be into G722 codecs and the like. They have about 40mS
roundtrip which is more than enough to induce a stutter in most
people.
--
Cheers
Dave.
Dave Liquorice
>> It's only then that you realise just how terrible the landline is,
>> compared to VoIP we've become used to.
>
> An ordinary landline with good phones can give decent enough quality.
> Trouble is people have got used to nasty mobile phones.
Quite agree and without the horrendous delay that mobiles have, not
to mention the distortion and codec artifacts. I've not been
impressed with the little bits of playing I've done with VoIP just as
appauling as mobiles but with the added complication of numnerous
hoops to jump through to make it work half reliably.
If VoIP can provide a "plug in and use" system that requires minmal
or no set up, round trip delays below a few mS (echo cancellation is
never good enough), no distortion, no codec artifacts if the
connection starts to struggle and better than 300 to 3kHz bandwidth
then it might start to rival POTS or ISDN. Oh and I don't know of
anybody that I currently call via the PSTN that has VoIP available...
--
Cheers
Dave.
Eusebius
http://www.maplin.co.uk/Module.aspx?ModuleNo=30352
Is this a true hybrid ?
andy
Dave Plowman (News)
<0efa31d9-dad2-4e03...@j4g2000yqe.googlegroups.com>,
> http://www.maplin.co.uk/Module.aspx?ModuleNo=30352
The Q&A session is a bit worrying - they talk about ground loops if used
with a PC. Twas my understanding *any* connection to the line had to be
via an isolating transformer which of course removes any ground issues.
--
*The longest recorded flightof a chicken is thirteen seconds *
Dave Liquorice
>> Anybody seen this cheap interface from Maplin?
>>
>> http://www.maplin.co.uk/Module.aspx?ModuleNo=30352
>>
>> Is this a true hybrid ?
No, it's using the hybrid in the telephone.
> The Q&A session is a bit worrying - they talk about ground loops if used
> with a PC. Twas my understanding *any* connection to the line had to be
> via an isolating transformer which of course removes any ground issues.
It's not connecting to the two wire line but to the four wire circuit
between the telephone base and the handset. As it causes hum I
suspect any "isolation" is just a capacitor and the switch selects
which pair of the four wire is connected to the 3.5mm plug. As you
say an isolating transformer should cure any hum.
--
Cheers
Dave.
Dave Plowman (News)
Ah - didn't read the description properly. Just how many phones use this?
Can't say I've ever seen it.
--
*Depression is merely anger without enthusiasm *
Dave Liquorice
>> It's not connecting to the two wire line but to the four wire
circuit
>> between the telephone base and the handset.
>
> Ah - didn't read the description properly. Just how many phones use
> this?
What, 4 wire to the handset or plugin handsets? I don't think I've
ever seens a phone that isn't 4 wire to the handset. Plugin handsets
are quite common, some times not obvious as the plug is hidden under
the base unit and hard wired into the handset.
--
Cheers
Dave.
Frank Erskine
<allsortsn...@howhill.com> wrote:
>On Mon, 23 Nov 2009 10:04:18 +0000 (GMT), Dave Plowman (News) wrote:
>
>>> It's not connecting to the two wire line but to the four wire
>circuit
>>> between the telephone base and the handset.
>>
>> Ah - didn't read the description properly. Just how many phones use
>> this?
>
>What, 4 wire to the handset or plugin handsets? I don't think I've
>ever seens a phone that isn't 4 wire to the handset.
Most old 300-type (bakelite) phones are 3-wire (plaited cord) to the
handset.
--
Frank Erskine
Dave Plowman (News)
Dave Liquorice <allsortsn...@howhill.com> wrote:
Plug in handset. And I've had a fair few phones apart in my time. ;-)
--
*Why is "abbreviated" such a long word?
jkn
>
> Phone lines aren't the same as "line input"
>
> Don't do what you are apparently thinking of doing. You will ground one
> side of the balanced phone circuit and this will bring up a ground fault
> alarm in the exchange, which may or may not generate a fault call for
> which you could be charged. You need to use an isolation transformer,
>
> Better to get a phone with an inbuilt headset adaptor such as the
> Plantronics ones you have found.
Much better than the Maplin sort of this are the adapters Retell
Recorders do:
http://www.retellrecorders.co.uk/
Their '703N' adapter (dunno if still manufactured, but available on
eBay) can be USB powered and interfaces from a Telephone headset
adapter to a PC line input. As said elsewhere, if you record that and
filter to around 3000Hz you can a perfectly decent recording.
J^n