The Business Phone E ID Card Series was a card telephone system allowing each user to make a call using the dedicated ID card. Calling a number outside the system's premises was possible only when the ID card was used. One system could register up to 127 ID cards and supported multiple cards for the same user. Each card could register up to 20 abbreviated numbers. These ID cards were personal cards with unique ID numbers registered in advance, allowing call charges to be managed for each user.

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