Configuration of Clock Source Using NMMGR

Refer to Table 3-1 “Clock Source Configuration” to configure the clock source parameter using NMMGR:

Direct Connect (2 ACC — connected back-to-back using loopback cable).
Connected to MODEM (or External DCE device).
Direct Connect (ACC and PSI connected back-to-back using loopback cable).




	NOTE: Auto dial is not supported on ACC (outbound Dial is not supported, but inbound connections are supported). Configure Modem Type to 0 (which is leased or Direct Connect).

When the WAN port is externally connected to the DCE (like a modem) which provides an external clock, then configure Clock source as External.

When connecting ACC on one system to ACC on other systems using a loopback cable (Null Modem):

Clock source in one system should be configured for 1 (External clocking) and another should be connected for 0 (internal clocking).
When connecting ACC on one system to a PSI on a different system (using loopback cable), always configure Clock source on the ACC port to the internal clocking.
Local Mode in one should be 6 (DCE) and another one must be 5 (DTE).

The configured clock of each port must match the corresponding end of the loopback cable. The end of the cable labeled internal goes to the side configured as internal clocking.

Table 3-1 Clock Source Configuration

	LOOPBACK Cable End	NMMGR Configuration Fields
		Physical Interface	Clock Source	Local Mode
Direct Connect	External	0 (RS-232)	1 (External)	5 (DTE) or 6 (DCE)
	Internal	0 (RS-232)	0 (Internal)	6 (DCE) or 5 (DTE)
	External	1 (V.35)	1 (External)	5 (DTE) or 6 (DCE)
	Internal	1 (V.35)	0 (Internal)	6 (DCE) or 5 (DTE)
Connected to Modem	N/A	1 (V.35 or 0 (RS-232)	1 (External	6 (DCE) or 5 (DTE)
Direct Connect	Internal	0 (RS-232)	0 (Internal)	6 (DCE) or 5 (DTE)
ACC/PSI	N/A	1 (V.35)	0 (Internal)	6 (DCE) or 5 (DTE)
Connected to Modem	N/A	1 (V.25) or 0 (RS-232)	1 (External)	6 (DCE) or 5 (DTE)
Notes:
The RS-232 loopback cables are asymmetrical and are labeled "Internal" on one end and "External" on the other end. The configured clock modes of each port must match the corresponding end of the loopback cable. The V.35 loopback cables are symmetrical and may be connected either way round. One port of the pair should be configured for internal (Int) clock and the other to use the (Ext) clock mode.

Configuration of Clock Source Using NMMGR

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