Iskra ETA 80 / Dialatron Carrera 1 - UK Vintage Radio Repair and Restoration Discussion Forum

hsbhachu3d · 20th Jun 2015, 5:35 pm

I remember having an ivory cream version this phone as a kid. I never really used it as it was a phone my gradpa had given me to play with. I got as far as plugging it in and noticing that the mic was dead after dialling 999 to test it (LOL) Anyways, I remember it was solely pulse. I went to my nan's house and she had the red version of it and it was touch tone!! (dtmf) I got to know later from my dad that the phone my nan had was just a well made replica but he wasn't sure either. The hadset did feel lighter than the cream pulse one I had.

Anyway, to the point, were these phones made with touch tone or were they only pulse? The reason I'm asking is that I have acquired one and it is the original pulse one. It has little pot at the bottom to change pitch (called 'tone') of the ringer and also a ringer volume pot.

As far as memory serves, I saw these phones on a www.etsy.com and some had the little 'tone' knob like mine where as others just had the hole with no knob. This obviously tells me that those have a different board inside. I want to get one of them if these really came in dtmf tone.

And yes, pulse to dtmf converters are available but they're terrible when using button phones as you'd have to wait for the pulses to complete, wait for the DTMF tone and then dial the next number. Bad enough if you're dialing a 0 and having to wait for 10 pulses followed by the DTMF tone before dialing the next number.

julie_m · 20th Jun 2015, 7:06 pm

I doubt they had digital exchanges there, when Yugoslavia existed; so the phones probably were all made for pulse-dialling only.

But that's not to say that the phone-line driver ICs they used weren't actually capable of tone-dialling, if the right two pins were shorted ...... However, to say any more would require a look inside the phone and a good search for data sheets.

hsbhachu3d · 21st Jun 2015, 11:15 am

The IC inside is an EMS 2560A. I've managed to get hold of a datasheet if it helps

julie_m · 21st Jun 2015, 11:35 am

That's not a data sheet; it's an error message! And I can't seem to find much myself.

It could be an Eastern European clone of a Western IC, given an innocuous renumber to avoid accusations of plagiarism .....

hsbhachu3d · 21st Jun 2015, 2:37 pm

LOL, I have no idea myself

let me repost
Here you go

Well the IC is an M2506A. There's a fair bit online about it.

julie_m · 21st Jun 2015, 3:17 pm

Nope; that is just a pulse-dialling IC, with no facility for tone-dialling

It drives transistors to simulate the pulse and off-normal contacts of a mechanical dial, and also provides mute and last-number redial functionality.

hsbhachu3d · 21st Jun 2015, 7:13 pm

Haww that's a bit sad though .. I will see if I can have a work around.

julie_m · 21st Jun 2015, 8:03 pm

You might be able to transplant the guts of a more modern phone into the housing, retaining the original keypad and handset .....

hsbhachu3d · 21st Jun 2015, 9:06 pm

I did it! The only issue I had was with the * key that was wired with the 369# line. I cut off the connections to the # key with a blade and connected it to the 0# line using thin coated wires. The ringer works too. I also put the original switch on a DIY board and wired it on where the new board's switch was meant to be and glued it to the chassis. The pot for ringer level is done too. The mic and earpiece just went on directly and it all works great. Checked with a DTMF translator app on my phone. Dials out, rings, everything works as original. I also glued in some weights on all 4 sides of the phone to give it that weighty feel that it's original 1.5mm board gave.

20th Jun 2015, 5:35 pm	#1
hsbhachu3d Pentode Join Date: Nov 2013 Location: Coventry, West Midlands, UK. Posts: 199	Iskra ETA 80 / Dialatron Carrera 1 I remember having an ivory cream version this phone as a kid. I never really used it as it was a phone my gradpa had given me to play with. I got as far as plugging it in and noticing that the mic was dead after dialling 999 to test it (LOL) Anyways, I remember it was solely pulse. I went to my nan's house and she had the red version of it and it was touch tone!! (dtmf) I got to know later from my dad that the phone my nan had was just a well made replica but he wasn't sure either. The hadset did feel lighter than the cream pulse one I had. Anyway, to the point, were these phones made with touch tone or were they only pulse? The reason I'm asking is that I have acquired one and it is the original pulse one. It has little pot at the bottom to change pitch (called 'tone') of the ringer and also a ringer volume pot. As far as memory serves, I saw these phones on a www.etsy.com and some had the little 'tone' knob like mine where as others just had the hole with no knob. This obviously tells me that those have a different board inside. I want to get one of them if these really came in dtmf tone. And yes, pulse to dtmf converters are available but they're terrible when using button phones as you'd have to wait for the pulses to complete, wait for the DTMF tone and then dial the next number. Bad enough if you're dialing a 0 and having to wait for 10 pulses followed by the DTMF tone before dialing the next number. Attached Thumbnails

20th Jun 2015, 7:06 pm	#2
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Iskra ETA 80 / Dialatron Carrera 1 I doubt they had digital exchanges there, when Yugoslavia existed; so the phones probably were all made for pulse-dialling only. But that's not to say that the phone-line driver ICs they used weren't actually capable of tone-dialling, if the right two pins were shorted ...... However, to say any more would require a look inside the phone and a good search for data sheets. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

21st Jun 2015, 11:35 am	#4
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Iskra ETA 80 / Dialatron Carrera 1 That's not a data sheet; it's an error message! And I can't seem to find much myself. It could be an Eastern European clone of a Western IC, given an innocuous renumber to avoid accusations of plagiarism ..... __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

21st Jun 2015, 3:17 pm	#6
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Iskra ETA 80 / Dialatron Carrera 1 Nope; that is just a pulse-dialling IC, with no facility for tone-dialling It drives transistors to simulate the pulse and off-normal contacts of a mechanical dial, and also provides mute and last-number redial functionality. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

21st Jun 2015, 7:13 pm	#7
hsbhachu3d Pentode Join Date: Nov 2013 Location: Coventry, West Midlands, UK. Posts: 199	Re: Iskra ETA 80 / Dialatron Carrera 1 Haww that's a bit sad though .. I will see if I can have a work around.

21st Jun 2015, 8:03 pm	#8
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Iskra ETA 80 / Dialatron Carrera 1 You might be able to transplant the guts of a more modern phone into the housing, retaining the original keypad and handset ..... __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

21st Jun 2015, 9:06 pm	#9
hsbhachu3d Pentode Join Date: Nov 2013 Location: Coventry, West Midlands, UK. Posts: 199	Re: Iskra ETA 80 / Dialatron Carrera 1 I did it! The only issue I had was with the * key that was wired with the 369# line. I cut off the connections to the # key with a blade and connected it to the 0# line using thin coated wires. The ringer works too. I also put the original switch on a DIY board and wired it on where the new board's switch was meant to be and glued it to the chassis. The pot for ringer level is done too. The mic and earpiece just went on directly and it all works great. Checked with a DTMF translator app on my phone. Dials out, rings, everything works as original. I also glued in some weights on all 4 sides of the phone to give it that weighty feel that it's original 1.5mm board gave. Attached Thumbnails