Hi Aparna The cable combination which you have mentioned is having 7 wires means it is having 4X3 or 3X4 matrix for 12 keys. It means there are 4 scan lines and 3 return lines or 3 scan lines and 4 return lines. There is no power wire involved into that. Hence you have to switch on the circuit and check the wires using oscilloscope. If you get transitions between 0 to vcc on three lines means there are 3 scan lines and if you get transitions on 4 wires means there are 4 scan lines. These scan lines must be generated from the processor itself or there must be some keyboard controller on it. Regards, Girish R. Ghanekar
-----Original Message----- Sent: Thursday, 29 August 2002 12:20 PM To: Multiple recipients of list CHIPDIR-L Hello, I have a circuit for which I am doing some reverse engineering. There is a wire link to the LCD keypad. the keypad has 12 buttons on it. namely 1,2,3,4,5,6,7,8,9,0,#,* the wire has 7 wires one for power and apparently the rest of the 6 wires represent the 12 keys. I wanted to know is there any standard combination for the keys. I cannot apply power to check it out as I have to be careful not to blow the circuit. Can anyone help? How can I check? Regards, Aparna -- Author: aparna INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Author: Balekai, Krishna (IE03x) INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
