| Byte range | Header | Description | Options |
| 3201-3204 | jobid | job identification number | |
| 3205-3208 | lino | line number (only one line per reel) | |
| 3209-3212 | reno | reel number | |
| 3213-3214 | ntrpr | number of data traces per record | |
| 3215-3216 | nart | number of auxiliary traces per record | |
| 3217-3218 | hdt | sample interval in microsecs for this reel | |
| 3219-3220 | dto | same for original field recording | |
| 3221-3222 | hns | number of samples per trace for this reel | |
| 3223-3224 | nso | same for original field recording | |
| 3225-3226 | format | data sample format code: | 1 = as recorded (no sorting) 2 = CDP ensemble 3 = single fold continuous profile 4 = horizontally stacked |
| 3227-3228 | fold | CDP fold expected per CDP ensemble | |
| 3229-3230 | tsort | trace sorting code: | 1 = as recorded (no sorting) 2 = CDP ensemble 3 = single fold continuous profile 4 = horizontally stacked |
| 3231-3232 | vscode | vertical sum code: | 1 = no sum 2 = two sum ... N = N sum (N = 32,767) |
| 3233-3234 | hsfs | sweep frequency at start | |
| 3235-3236 | hsfe | sweep frequency at end | |
| 3237-3238 | hslen | sweep length (ms) | |
| 3239-3240 | hstyp | sweep type code: | 1 = linear 2 = parabolic 3 = exponential 4 = other |
| 3241-3242 | schn | trace number of sweep channel | |
| 3243-3244 | hstas | sweep trace taper length at start if tapered (the taper starts at zero time and is effective for this length) | |
| 3245-3246 | hstae | sweep trace taper length at end (the ending taper starts at sweep length minus the taper length at end) | |
| 3247-3248 | htatyp | sweep trace taper type code: | 1 = linear 2 = cos-squared 3 = other |
| 3249-3250 | hcorr | correlated data traces code: | 1 = no 2 = yes |
| 3251-3252 | bgrcv | binary gain recovered code: | 1 = yes 2 = no |
| 3253-3254 | rcvm | amplitude recovery method code: | 1 = none 2 = spherical divergence 3 = AGC 4 = other |
| 3255-3256 | mfeet | measurement system code: | 1 = meters 2 = feet |
| 3257-3258 | polyt | impulse signal polarity code: | 1 = increase in pressure or upward
geophone case movement gives negative number on tape 2 = increase in pressure or upward geophone case movement gives positive number on tape |
| 3259-3260 | vpol | vibratory polarity code: code seismic signal lags pilot by | 1 337.5 to 22.5 degrees 2 22.5 to 67.5 degrees 3 67.5 to 112.5 degrees 4 112.5 to 157.5 degrees 5 157.5 to 202.5 degrees 6 202.5 to 247.5 degrees 7 247.5 to 292.5 degrees 8 293.5 to 337.5 degrees |
Bytes 3261-3600 are currently unassigned
This information is basically as supplied in the segy.h file with the additions of the byte locations (reference to the start of the EBCIDIC header not the start of the binary header. All numbers in the binary header are integers.