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Pasternack Blog
As is common in many industries, there are often internal acronyms or company part names/standards that may eventually spread to the larger industry. This is the case for some of the types of twinaxial and triaxial transmission line components, such as TRB Plug to TRB Jack Right Angle Adapters, that are present in the RF industry. This blog aims to help decipher some of these terms and help to illuminate the genesis of these terms.
Many of the following connector names or “styling” may have originated with Trumpeter, which is a connector manufacturer that has been around since the 1960s, and is now a subsidiary of Cinch Connectivity, now Belfuse. It is unclear if the 3 letter codes for the twinax and triax product lines are acronyms or merely just codes chosen for organization purposes.
Twinaxial Connectors (twinax) and Triaxial Connectors(triax)
Twinaxial connectors and cabling are based on a two-conductor twisted wire line that is also balanced. This means that these transmission lines have a specific impedance and enhanced shielding around both wires. Essentially, twinaxial lines are like coaxial transmission lines but with two center conductors and an outer shielding.
Triaxial cables are like coaxial cables but with an additional outer shielding layer which is isolated from the signal-carrying inner and outer conductors. Both twinaxial and triaxial transmission lines offer enhanced noise shielding compared to coaxial transmission lines but are not generally designed for frequencies beyond a few hundred megahertz.
TRB/TRT Connectors
TRB connectors are available with 2, 3, or 4 bayonet lugs or as push-on connectors. These twinax/triax connectors are similar to BNC connectors and even have the same outer dimensions. This connection type is most often used with applications where noise immunity is a priority and signal frequency doesn’t exceed ~500 MHz. The TRT connectors are similar to the TRB connectors with the exception that the TRT connectors are threadlock connectors. In this way, TRT is like the twinax/triax variation of TNC for BNC connectors. These are also the same size as BNC/TNC connectors, and are also well suited to applications where “noise-free guarded” circuits are used.
TRS/TTM Connectors & TPS/TCM Connectors
The TRS series are miniature 2, 3, 4 lug and push-on twinax/triax connectors used in high density applications, or where weight reduction compared to TRB is critical. The TTM connectors are the threaded version of the TRS connectors and are miniature versions of the TRT connectors. The TTM and TRS push-on versions are designed for blind-mate rack and panel applications. These connectors are the same size as the TPS/TCM connectors. The TPC/TCM connectors seem to be similar to the TRS/TTM connectors but are coaxial and not twinax/triax connectors.
TRC/TRN Connectors
TRC is the standard 2 and 3 lug bayonet “C” sized concentric connectors, while TRN is the threaded version of the TRC. These are larger than the TRB/TRT variety.
TWBNC/TWTNC Connectors
The TWBNC is a miniature two-pin polarized twinax/triax 2-lug connector. The TWTNC is the miniature two-pin polarized threaded version of the TWBNC. These are non-concentric designs and have not been recommended for new designs for some time.
