One nice "consumer" feature of the display is the Display Mode button, found only on the remote control. (By the way, this is a good time to mention that the 670 needs the remote control for quite a few of its functions.) The Display Mode button selects one of three modes. When the display is "ON," all indicators are lit. When in the "OFF" mode, the level meters and Margin Indicator turn off. This merely makes the display look a little less "busy" without the level meters constantly lit and moving. But the nifty mode is the "AUTO" mode. In this mode, the entire display shuts off when the unit is playing, making the unit look as though it's not even turned on! There isn't even a "Power On" light. Then, when any of the transport controls are pressed -- rewind, fast forward, pause, etc. -- the display lights up so you can see what you're doing! Very good, late night, bedside manners...if you plan to have a DAT deck on your nightstand.
Anyway, there are indicators to show what display mode is in effect. There's a "CAUTION" light that warns of condensation in the unit. A "COPY PROHIBIT" indicator lights when an attempt is made to make a digital copy of a SCMS protected tape. (The manual kindly suggests you then use the analog inputs.) The Margin Indicator mentioned earlier is a nice feature. This numerical display shows how much headroom or margin there is between the highest peaks of the input signal and 0dB -- a helpful aid when setting input levels. The peak level meters also function as a "frequency map." When the "4" and "COUNTER MODE" buttons on the remote are pressed simultaneously, the peak level meters switch to the Frequency Map mode and indicate the sampling frequencies used to record the tape. If you have a tape with different segments recorded at different sampling rates, this display can accurately show you how inconsistent your recording is. Other than that, this function seems to fall into the category of bedside manners along with the dimming display.
There's a "REHEARSAL" indicator on the display that lights when the unit's Rehearsal function is engaged. This function lets you adjust the position of the Start or Skip IDs. There are a couple of other indicators on the display that light up when the 670's Repeat and Program functions are enabled. The 670 will repeat playback of a single program, the entire tape, or a selected number of programs for sixteen times then shut off. Program Play is easily accomplished using the remote control. There is no number keypad on the front panel of the 670, so the remote control must be used to enter the program numbers to be played back. Up to sixty selections can be programmed into the unit's memory.
The DTC-670 also offers Music Scan with variable "scan time" (the time each program plays before going to the next) adjustable from one to fifteen seconds. The Music Scan function also works in reverse, from the end of the tape to the beginning, and a "MUSIC SCAN" indicator lights when the mode is enabled. Of course, you also get the usual Skip Play function which seems most useful when recording music directly from the radio and you wish to automatically "skip" stopsets and such upon playback.