Right - An 1870s buckle worn by local provincial gendarmerie. The Ottoman script on the buckle reads: 'Vilaet (perfecture) of Girit (island of Crete)'. This style of buckle was used from the 1870s till 1898, with the end of Ottoman rule in Crete. This buckle likely relates to events in Crete, which from the mid 1880s (till end of the 1890s), formed under its vila (governor) special units of Gendarmerie .
 Senisik, P. 2011 The Transformation of Ottoman Crete: Revolts, Politics and Identity in the Late Nineteenth Century. I.B.Tauris.
Below/Right - A picture of Lebanese soldiers, 1861-1914. The .British General Staff. (1995) 1916 Handbook of the Turkish Army. Battery Press, Nashville: 56, describes the Lebanon Militia, "where its duties are chiefly those of police". Also describing the ranks -soldiers as wearing uniforms that, "resemble that of a French Zouave: blue jacket with red braiding; they were in 1915 put into ordinary gendarme uniform".
Right - A very high quality made WW1 Turkish shoulder board, from a French private collection, which is accompanied with a period souvenir label identifying "Beirut, 1918" as the origin. This board represents some type of rank (similar to other WW1 Ottoman rank insignia in this period). Combination of double silver metallic cords around the edge, and what appears to be two silver metallic bars, separated by a red line (as well as the two red edging lines).
From 1909, the Gendarmes, and in 1915/16 the Army junior officers, adopted alternative cuff ranks. The ‘Onbasi’ wore one cuff stripe, in red service/branch colour.
All adopted new style of shoulder cords/boards with a 1cm thin red line beginning from the button. This 'red line', was the red base of the board, with gilt cord-lace added around the edge.
Officers above the rank of Captain (ie Major and above), were drawn from the Imperial Army, and wore that rank insignia.
Right - This illustration is extracted from WW1-period Gendarmerie Dress Regulations: Article 29: "The (Gendarmerie) Jacket collar is flat, with a 7 centimeters x 3.5 centimeters light red color patch, set half-a-centimeteredge from the front side of the collar's edge. Provided with yellow metal plates sewn-on. The right-hand side, containing the individual soldier's regiment number, and the left side containing the name of the province as belonging to."
Above - The extracted page from the dress regulations show two two types of 'Province' plates, one displaying the word for "school" as well as the province location. When enlisted, a "grendarme is trained at the local recruit school, the course lasts five months". 
According the 1916 Turkish Army Handbook, this identified approximately eight standing regiments of Gendarmerie composed of brigaded foot battalions, and mounted squadrons   :
 British General Staff. (1995) 1916 Handbook of the Turkish Army. Battery Press, Nashville: 200-201.
 Ibid: 98.
 According the 1916 Turkish Army Handbook, this identified approximately eight standing regiments of Gendarmerie brigaded foot battalions, and mounted squadrons. Right - Extracted from the 1916 Turkish Army Handbook (p.101), this table shows the total numbers of mounted Gendarmes, in 1912.