1

PS: Talker identifier

2

IMP: Datagram identifier

3

D: Sentence specifier

4

tt: Time

5

dd: Date

6

M: Type of measurement •  D: Depth •  T: Temperature •  C: Catch •  B: Bottom •  N: No sensor •  M: Marker

7

U: Unit M (metres), f (feet) or F (fathoms) for depth measurements C (Celsius) or F (Fahrenheit) for temperature measurements

8

S: Source The number (1, 2 or 3) of the sensor providing the current data values.

9

C: Channel The number (1 to 30) of the communication channel for the current data source

10

V: Value The magnitude of the current sensor measurement

11

Cr: Change rate The magnitude of the current depth or temperature measurement

12

Q: Quality •  0: No connection between the sensor and the receiver •  1: One or two telemetry pulses are lost, current value is predicted. •  2: The current data value is reliable.

13

In: Interference •  0: No interference •  1: Interference is detected

14

SL: Signal level The signal level of the telemetry pulse measured in dB // 1 µPa.

15

NL: Noise level The average noise level of the current channel measured in dB // 1 µPa.

16

G: current gain, 0, 20 or 40 dB

17

Cb: Cable quality •  0: Cable is not connected. •  1: Cable is OK. •  2: A short circuit, or the hydrophone current is too large.

18

error: Error detected 0 when no error is detected. A number greater than 0 indicates an error condition.

19

chksum: Checksum The checksum field consists of a "*" and two hex digits representing the exclusive OR of all characters between, but not including, the "$" and "*" characters.