When using the no arp arpa command on a interface, I assume the command disables the ablitiy to send arp requests, but does it also disable the ability to respond to arp requests?

What is the max number of characters supported in an AT command string? The hardware being used is the 8 port Analog Modem card in the 3640 router.Thanks

I am trying to figure a way to use a virtual interface, or rotary type config on a 3640 to do reverse telnet to the next available modem port, instead of specifying a specific modem port, and then issue AT commands to dial a pager.