The provided Crystal GSM FCT gives better voice quality for all circuitry supports. It can be the best communication mode when the primary communication fails. This FCT can easily be connected with PCO and billing machines. It has the best voice call line applications. Our Crystal GSM FCT can be attached to an EPABX and PTP communication devices in multi-user environments. This FCT has ARJ11-type interface with optional V22 payphone management modem.