Do you mean SOUNDTRAXX's PTB-100 booster?If so,it goes between the PROGRAMMING outputs of the command station (in this case a DCS51) and the programming TRACK itself.
It also needs power. On the other Digitrax systems, the power wires come in as a pair of wires. On the DCS-51, the power supply plugs in to the unit. You need to tap into these wires. One way to do this without altering anything is to get a matching socket and plug at radio shack - wire the socket to the plug but also connect a second pair of wires to power the PTB-100. Plug the power supply into the socket, plug the plug into the Zephyr, and off you go.
Really you should not need the PTB-100 with the Zephyr. The biggest issue is that CV29 doesn;t get set when changing the address - a manual program of CV29 to the correct value uses fixes everything. This doesn;t happen when using a DT40x throttle instead of the Zephyr console. And int he case of studdorn decoders (I avoid these like the plague), there is always Blast Mode, which you should find in the manual. Remove all locos from the program track AND main track, excepot the one you are trying to program, when using Blast Mode. If Blast Mode won;t work, something else is wrong - Blast Mode sends full power to the program track, not the usual low current programming pulses. This gets around those decoders with high inrush currents.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
You can also use a separate power supply. Soundtraxx recommends a 15 volt DC supply that supplies a minimum of 500 ma. I use a 15 VDC wall wart rated at 2 amps from Litchfield Station.
Joe