When you enter a number to dial from your phone, a DigitMap Processor (DMP) uses the PHONE Port Digitmap to (possibly) reformat it and then determine the best match available. The ITSPA and ITSPB DigitMap's are part of the PHONE Port DigitMap via indirection [(Msp1), (Msp2), and possibly (Mpli)]. Then the result from the DMP is passed through the OutboundCallRoute, one route at a time from left to right, looking for the first route that matches. When a suitable route is found, that port is used for the call.