Call progress analysis is performed in a telephone system employing
different in-band signaling plans are used. From address information for
a call destination in a call initiation message, it is determined which
type of in-band signaling plans is utilized by equipment associated with
the call destination, for example by examining country codes in a dialed
telephone number. Based upon the determined signaling plan type, a
corresponding type of call progress analysis resource is selected and
allocated for use with the call. The analysis resource may include a
digital signal processor (DSP) programmed with an analysis routine
tailored to the determined signaling plan. The DSP may be pre-programmed
with such a routine or may be loaded at call time with analysis
parameters appropriate to the signaling plan. The telephone system may
employ a packet network and packet-based telephony transmission, a media
gateway controller or a Session Initiation Protocol (SIP) proxy server,
an a media server. A telephone network employing more traditional
time-division-multiplexed (TDM) based media transmission may also be
utilized.