The TA 900 and 900e series are fixed port VoIP IADs and support the following number of FXS and FXO ports based on the chassis. All of the TA 900e series units have one built in FXO port for remote survivability. The chassis are not upgradeable, therefore care should be taken when planning for the number of analog ports required for your application.
Using the dial plan and user accounts, specific inbound calls can be sent to a particular port by using the DNIS received for that call. DNIS digits can be sent out of an FXS port on the TA 900 and TA900e series as DTMF tones, but A2.04 code is a minimum requirement for this feature. This is often used for fax servers that receive DNIS via DTMF tones in an off hook condition.
The TA900 and TA900e series units are designed for termination of SIP trunks from approved feature servers and currently have no support for TDM voice circuit termination from the PSTN. These units do not support TDM maps for mapping TDM DS0 channels from a carrier provider T1 circuit directly to an FXS port.