Yes, there is a 40-character command buffer limit in the PowerBook modem, but there is a workaround.
By using the ; (semicolon) command, you can enter phone numbers (or any command for that matter) longer than 40 characters. You will need to break the phone number up into two separate commands, each less than 40 characters. The semicolon (;) command returns the modem to local command state after dialing. You must put the semicolon (;) at the end of the dialing command.
For example, if you want to dial (408) 555-1212, follow these steps:
1) Enter: ATDT408555;
2) Press RETURN.
3) Wait for OK.
4) Enter: ATDT1212
5) Press RETURN.
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