IEC 61169-38:2008 which is a sectional specification, provides information and rules for the preparation of detail specifications for series TMA r.f. connectors together with the pro forma blank detail specification. Series TMA connectors have a characteristic impedance of 50 O and are normally used with R.F cables or with microstrip in microwave fields that has a blind-entry and middle low-power. The connectors are usable up to a frequency of at least 6 GHz.