Connect US voltage modem to the European voltage Macintosh - is it safe?

[Aektann]

I have Apple Personal Modem made for 110v. It powers up through a good voltage transformer which converts the power from 220 to 110v. Is it safe to plug this modem to the serial port of my European Macintosh 512k (220v nattive)? I suspect there could be some grounding issues but I’m not sure.

 

[LaPorta]

I wouldn’t think there is an issue as the DC voltages inside the machines are the same for US or international. However, I’m no expert.

 

[Nixontheknight]

I have Apple Personal Modem made for 110v. It powers up through a good voltage transformer which converts the power from 220 to 110v. Is it safe to plug this modem to the serial port of my European Macintosh 512k (220v nattive)? I suspect there could be some grounding issues but I’m not sure.

it should be fine, there's no direct mains voltages being shared between the two, only 5V and maybe 12V

 

[Skate323k137]

it should be fine, there's no direct mains voltages being shared between the two, only 5V and maybe 12V

Agreed.

If you're really paranoid just be sure both the step-down and computer are properly grounded (earthed).

 

[cheesestraws]

Yeah. If you're not fine here, something's badly wrong with your step-down converter.

 

[stepleton]

I've done this with an 120VAC Apple Modem 300 plugged into various 240VAC systems, and aside from struggling to keep up with the incredible speed of the device, I've encountered no problems.

HOWEVER, if your power outlet is incorrectly wired, with live and neutral reversed, then you could run into trouble. This is not too common, but it's something you can easily do by accident if you're also using a plug adaptor for different types of power outlet (e.g. a US NEMA 5-15 plug to a UK BS 1363 plug). Some of the really dodgy ones can't be relied upon to connect live to live and neutral to neutral, or they lack the features that ensure that you plug them in with the correct orientation. These cheap adaptors are never worth it!

 

[cheesestraws]

That's also a very good point.