AWG stands for "American Wire Gauge". It's used to represent measures of cable length and section.

This is an AWG conversion table:

AWG	Diam. mm	Area mm2		AWG	Diam. mm	Area mm2
1	7.35	42.40		16	1.29	1.31
2	6.54	33.60		17	1.15	1.04
3	5.86	27.00		18	1.024	0.823
4	5.19	21.20		19	0.912	0.653
5	4.62	16.80		20	0.812	0.519
6	4.11	13.30		21	0.723	0.412
7	3.67	10.60		22	0.644	0.325
8	3.26	8.35		23	0.573	0.259
9	2.91	6.62		24	0.511	0.205
10	2.59	5.27		25	0.455	0.163
11	2.30	4.15		26	0.405	0.128
12	2.05	3.31		27	0.361	0.102
13	1.83	2.63		28	0.321	0.0804
14	1.63	2.08		29	0.286	0.0646
15	1.45	1.65		30	0.255	0.0503

RS-232 (Recommended Standard 232, also known as EIA/TIA RS-232C) is an interface that designates a standard for the exchange of a series of binary data between a DTE (Data Terminal Equipment) and DCE (Data Communication Equipment , Data Communication Equipment), although there are others in which the RS-232 interface is also used. An equivalent definition published by the ITU is called V.24. The RS-232 is a connectorDB-25 type (25-pin), although it is normal to find the version of 9-pin (DE-9, or popularly also called DB-9), cheaper and even extended to certain types of peripherals (such as serial mouse PC).