2.7.  Troubleshooting the SCxbus Cabling

Communications and clocking on the SCxbus can be monitored for troubleshooting purposes by connecting your monitoring device to the connector pins listed in Table 6.  SCxbus Pin-Outs. This table lists the SCxbus signals versus connector pin-outs and provides a description of each signal. All cabling, connectors and signaling conform to the requirements defined in The SCSA Hardware Model Specification, Version 3.0, available from Dialogic Corporation. The binary state of line is as follows:

• 1 = "- SCxbus signal" terminal is negative with respect to the "+ SCxbus signal" terminal
• 0 = "- SCxbus signal" terminal is positive with respect to the "+ SCxbus signal" terminal.

The SCX160 SCxbus Adapters are connected to each other via a 34 signal twisted pair SCxbus Y-cable. Both ends of the cable must be terminated to meet RS485 requirements. All signals on the SCxbus cable are common between all connected devices. See Figure 5.  SCxbus Cabling, Typical, for typical SCxbus cabling between nodes.

Table 6.  SCxbus Pin-Outs

Pin	SCxbus Signal	Pin	SCxbus Signal	Description
1	- SCxSD0	35	+ SCxSD0	BSDS (Bi-directional Serial Data Stream) #1
2	- SCxSD1	36	+ SCxSD1	BSDS #2
3	- SCxSD2	37	+ SCxSD2	BSDS #3
4	- SCxSD3	38	+ SCxSD3	BSDS #4
5	- SCxSD4	39	+ SCxSD4	BSDS #5
6	GND	40	GND	Connect to PCB
7	- SCxSD5	41	+ SCxSD5	BSDS #6
8	- SCxSD6	42	+ SCxSD6	BSDS #7
9	- SCxSD7	43	+ SCxSD7	BSDS #8
10	- SCxSD8	44	+ SCxSD8	BSDS #9
11	- SCxSD9	45	+ SCxSD9	BSDS #10
12	- SCxSD10	46	+ SCxSD10	BSDS #11
13	- SCxSD11	47	+ SCxSD11	BSDS #12
14	- SCxSD12	48	+ SCxSD12	BSDS #13
15	- SCxSD13	49	+ SCxSD13	BSDS #14
16	N.C.	50	GND	Connect to PCB
17	TERMPWR	51	TERMPWR	Termination power
18	TERMPWR	52	TERMPWR	Termination power
19	N.C.	53	N.C.	No Connection
20	- KREF	54	+8 KREF	8 kHz reference clock
21	GND	55	GND	Connect to PCB
22	- L_SCxCLK	56	+ L_SCxCLK	System clock, left
23	- L_SCxFSYNC	57	+ L_SCxFSYNC	Frame sync, left
24	- SCxMC	58	+ SCxMC	Message channel
25	- SCxSD20	59	+ SCxSD20	BSDS #21
26	- SCxSD19	60	+ SCxSD19	BSDS #20
27	- SCxSD18	61	+ SCxSD18	BSDS #19
28	- SCxSD17	62	+ SCxSD17	BSDS #18
29	- SCxSD16	63	+ SCxSD16	BSDS #17
30	GND	64	GND	Connect to PCB
31	- SCxSD15	65	+ SCxSD15	BSDS #16
32	- SCxSD14	66	+ SCxSD14	BSDS #15
33	- R_SCxCLK	67	+ R_SCxCLK	System clock, right
34	- R_SCxFSYNC	68	+ R_SCxFSYNC	Frame sync, right

Figure 5.  SCxbus Cabling, Typical

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