SIM card - how far from the phone?
john_s
Posts: 369
I need to place a sim card remotely and away from its own inside the phone socket using some kind of extension cable/bus.
So I wonder - what is the safe distance to communicate between a cellular phone and its SIM card but placed kind of "remotely" ?
Can I go say 1m apart? How about 3m, etc ?
Is there any spec for that kind of communication?
Update: according to http://www.nxp.com/documents/application_note/AN10914.pdf
"The minimum clock frequency is 1 MHz, the maximum GSM clock frequency is 4 MHz, while the maximum
SMART-card interface clock frequency can go up to 20 MHz."
So we're talking f/372= 4MHz/372= 10.752kHz for sim card communication.
Let's say it can go as high as 38kb/s as in Maxim appnote.
I figure that the extender made out of 8 twisted pair wires can go quite a distance and at least 3m apart from the phone.
So I wonder - what is the safe distance to communicate between a cellular phone and its SIM card but placed kind of "remotely" ?
Can I go say 1m apart? How about 3m, etc ?
Is there any spec for that kind of communication?
Update: according to http://www.nxp.com/documents/application_note/AN10914.pdf
"The minimum clock frequency is 1 MHz, the maximum GSM clock frequency is 4 MHz, while the maximum
SMART-card interface clock frequency can go up to 20 MHz."
So we're talking f/372= 4MHz/372= 10.752kHz for sim card communication.
Let's say it can go as high as 38kb/s as in Maxim appnote.
I figure that the extender made out of 8 twisted pair wires can go quite a distance and at least 3m apart from the phone.