User:Fenix t/sandbox

GND	TX1+	TX1-	VBUS	CC1	D+	D-	SBU1	VBUS	RX2-	RX2+	GND
GND	RX1+	RX1-	VBUS	SBU2	D-	D+	CC2	VBUS	TX2-	TX2+	GND

Connector pin usage in different cases

The below diagrams depict the pins of a USB-C socket in different usage cases.

USB 2.0/1.1

A simple USB 2.0/1.1 device mates with one pair of D+/D- pins. Hence it does not require any connection management circuitry and therefore is backward compatible with even the oldest USB devices. VBUS and GND provide 5V up to 500mA of power.

GND	TX1+	TX1-	VBUS	CC1	D+	D-	SBU1	VBUS	RX2-	RX2+	GND
GND	RX1+	RX1-	VBUS	SBU2	D-	D+	CC2	VBUS	TX2-	TX2+	GND

USB Power Delivery

USB Power Delivery uses one of CC1, CC2 pins for power negotiation up to 20V 5A (or whatever less the source can provide). It is transparent to any data transmission mode and therefore can be used together with any of them.

GND	TX1+	TX1-	VBUS	CC1	D+	D-	SBU1	VBUS	RX2-	RX2+	GND
GND	RX1+	RX1-	VBUS	SBU2	D-	D+	CC2	VBUS	TX2-	TX2+	GND

USB 3.0/3.1/3.2

In the USB 3.0/3.1/3.2 mode two or four high speed links are used in TX/RX pairs to provide 5 to 20 Gbps throughput. One of the CC pins is used to negotiate the mode. VBUS and GND provide 5V up to 900mA, in accordance to USB 3.0 specification.

GND	TX1+	TX1-	VBUS	CC1	D+	D-	SBU1	VBUS	RX2-	RX2+	GND
GND	RX1+	RX1-	VBUS	SBU2	D-	D+	CC2	VBUS	TX2-	TX2+	GND

Alternate Mode

In the Alternate Mode one up to four high speed links are used in whatever direction is needed. SBU1, SBU2 provide an additional lower speed link. If two high speed links remain unused, then a USB 3.0/3.1 link can be established concurrently to the Alternate Mode. One of the CC pins is used to perform all the negotiation. Also an additional low band bidirectional channel (other than SBU) may share that CC pin. USB 2.0 is also available through D+/D- pins. The available power may be 5V up to 500mA by default, 5V up to 900mA if USB 3.0/3.1 link is active or whatever the Power Delivery is providing.

GND	TX1+	TX1-	VBUS	CC1	D+	D-	SBU1	VBUS	RX2-	RX2+	GND
GND	RX1+	RX1-	VBUS	SBU2	D-	D+	CC2	VBUS	TX2-	TX2+	GND

Semi-automatic signal configuration:
old	new	The old system did not use blinking lights, except the subsidiary signal, but that one was not popular at that times. The pictures to the left present old and contemporary configuration with indication which colour chambers may blink if required. There is a principle, observed then and now that two chambers of the same colour must be separated by a chamber of other colour.

Old signals and their contemporary counterparts
old	description	contemporary
	stop the same expression	S1
	proceed at Vmax the same expression	S2
no equivalent for S3
	reduce speed to 40 km/h different expression	S4
	stop at next signal the same expression	S5
no equivalent for S6-S9, S10a-S13a, S11
	proceed at 40km/h different expression	S10
	proceed at 40 km/h, stop at next signal the same expression	S13

Old warning shields and repeaters
warning shield	repeater	With warning shields there is a principle that the chambers illuminating together, although of different colours, cannot be adjacent to each other. This explains why the are two chamber of orange colour next to each other. With repeaters this principle is apparently not observed.

Old warning shields and repeaters and their contemporary counterparts
old		description	contemporary
		there will be stop at the signal the same expression
		there will be proceed at Vmax at the signal the same expression
		reduce speed to 40 km/h, there will be proceed at 40 km/h at the signal different expression

All legal signals on semi-automatic semaphores:
	S1 halt
Proceed or speed reduction order:
	S2 clear, proceed at Vmax S3 reduce speed to 100 km/h S4 reduce speed to 60 or 40 km/h S5 stop at next semaphore
Speed limit 100 km/h:
	S6 speed limit 100; will be Vmax after next semaphore S7 speed limit 100; will be 100 after next semaphore S8 speed limit 100; will be 60 or 40 after next semaphore S9 speed limit 100; will be stop at next semaphore
Speed limit 60 km/h:
	S10a speed limit 60 km/h; will be Vmax after next semaphore S11a speed limit 60 km/h; will be 100 after next semaphore S12a speed limit 60 km/h; will be 60 or 40 after next semaphore S13a speed limit 60 km/h; will be stop at next semaphore
Speed limit 40 km/h:
	S10 speed limit 40 km/h; will be Vmax after next semaphore S11 speed limit 40 km/h; will be 100 after next semaphore S12 speed limit 40 km/h; will be 60 or 40 after next semaphore S13 speed limit 40 km/h; will be stop at next semaphore

Subsidiary Signal
			Sz, the subsidiary signal (Pol. sygnał zastępczy) is a signal issued in case of malfunction. The first picture presents a typical case where dispatch can not change the signal from S1. The second picture presents a case where the semaphore is powered down. Third picture presents a special semaphore where only the Sz signal can be displayed. The train must stop and wait until Sz is issued.

Automatic semaphores

Automatic semaphores are used on lines equipped with automatic block signaling. Their colour language is the same as aspects S1-S5 of semi-automatic semaphores. The main difference regards S1 (red) signal - it can be passed with maximum speed of 20 km/h after full stop.

Automatic semaphores have their posts painted white (without red strips) to be easily distinguished apart from semi-automatic semaphores.

Automatic semaphores:
2-state ABS:
			S2 proceed S1 stop, train ahead
3-state ABS:
			S2 proceed (>1 block free) S5 stop at next semaphore (1 block free) S1 stop, train ahead
4-state ABS:
			S2 proceed (>2 blocks free) S3 reduce speed to 100 km/h (2 blocks free) S5 stop at next semaphore (1 block free) S1 stop, train ahead
other:
			S1a is a special-case aspect, which forbids passing a semaphore displaying it, just like S1 on semi-automatic semaphore. It is used for safety reasons, as for instance to forbid entering a tunnel during fire alarm. Other aspects are displayed normally, as in 3- or 4- state ABS. (dark) — on a track with bidirectional ABS, only the semaphores for currently set direction are glowing; opposite direction semaphores are dark. A driver who found himself aproaching a dark semaphore must stop the train and alarm the dispatch.

Warning shields

Warning shield sign

Warning shield (Pol. tarcza ostrzegawcza) is distant-only signal display. It is used on lines not equipped with ABS. Placed in the braking distance allow driver to stop before the semaphore they regard. Their colour language is the same as semaphore aspects S2-S5, making them technically a semaphore which is just incapable to display S1 (stop) aspect.

Their posts are painted grey and equipped with the warning shield sign.

Warning shields:
	Os1 there will be S1 (stop) at the semaphore
	Os2 there will be proceed with Vmax at the semaphore
	Os3 there will be speed reduction to 100 km/h at the semaphore
	Os4 there will be speed reduction to 40 or 60 km/h at the semaphore

Semaphore repeaters

When the semaphore aspect is not visible from the proper distance (because of track curves for instance), a semaphore repeater is installed to aid drivers. Up to three repeaters may be installed if needed. A semaphore repeater is not a substitute for a warning shield.

Their posts are painted grey and equipped with plates with Roman numerals: III, II, I where the "I" stands closest to the semaphore. Their color language is identical to warning shields, except the fact they also have continuously glowing white light, which informs that this is not a valid signal but a repeater.

Semaphore repeaters:
	Sp1 there will be S1 (stop) at the semaphore
	Sp2 there will be proceed with Vmax at the semaphore
	Sp3 there will be speed reduction to 100 km/h at the semaphore
	Sp4 there will be speed reduction to 40 or 60 km/h at the semaphore

The following table presents as example, a station-entry semaphore designated "B" displaying the aspect S13 (speed limit 40 km/h, stop at the next semaphore) preceded with warning shield and three repeaters:

warning shield		3rd repeater	2nd repeater	1st repeater	the semaphore
ToB		3SpB	2SpB	1SpB	B
braking distance
		visibility distance

Level crossing warning shields

Level crossing warning shield is placed in a braking distance before an automatic level crossing. The signal tells the driver whether automobile drivers are warned against a train (blinking red lights, barriers). Normally, level crossing warning shields display no signal (are dark). They light up in the front of an approaching train which is the first clue that the system is working correctly.

Level crossing warning shields signals are unrelated to other signals, therefore in case of Osp1 signal a train must proceed at 20 km/h regardless the higher speed allowed by last semaphore.

Their posts are painted black and white strips.

Level crossing warning shields
	Osp1 Automatic level crossing is not working properly. Train head must pass the crossing with speed limited to 20 km/h and be prepared for immediate stop.
	Osp2 Automatic level crossing operating properly. Proceed at normal speed.

Maneuver shields

Maneuver shield (Pol. tarcza manewrowa) is shunting signal, used exclusively on stations. A consist shunting on such signals must not leave the station. Maneuver shields are either stand-alone or incorporated into semi-automatic semaphores, which bear letter "m" on such occasion.

Stand-alone maneuver shields have their posts painted gray.

Maneuver shields:
		Ms1 shunting forbidden S1 stop and shunting forbidden
		Ms2 shunting allowed

Mechanical signals

Mechanical semaphore (day & night)
Sr1 stop	Sr2 clear	Sr3 clear slowly (40 km/h)
Mechanical warning shield
On/Od1/Ot1 expect stop	Od2/Ot2 expect clear	Ot3 expect clear slowly
Mechanical maneuver shield
M1 shunting forbidden	M2 shunting allowed

Category:Railway signalling by country