E1 PRI (ISDN) - Reset Procedure

Use the following procedure to disable and re-enable a troublesome ISDN PRI circuit.
Steps in RED apply to clocking, omit on large systems, or see below for media gateway info

A Primary Rate Interface (PRI) comprises 3 components, maintained in 2 loads:
- Voice channels, and clock: LD 60, associated data channel (DCH): LD 96.

1 LD 60: STAT

Note the LOOP number, and associated DCH (on channel 31) of your PRI. We must know these before we start!
The following STAT shows Loop 12 and DCH 5, but you must substitute YOUR values in the commands!

.stat                          ⇐ in LD 60

PRI2 LOOP 12 - ENBL           ⇐ Loop number
REF CLK: ENBL
SERVICE RESTORE: YES
ALARM STATUS: OOS  
CH 01 - DSBL DID   VOD  *           CH 02 - DSBL DID   VOD  *       ⇐ all channels are down 
CH 03 - DSBL DID   VOD  *           CH 04 - DSBL DID   VOD  *
:
CH 31 - DCH 5                 ⇐ D channel for this PRI shown at CH 31

2 Disable:

Overlay	Commands	Notes
LD 96:	DIS AUTO 5	disable auto recovery
	DIS DCH 5	disable d-channel
	STAT DCH 5	confirm d-channel is disabled
LD 60:	DISL 12	disable loop
	STAT 12	confirm loop is disabled
	DIS CC 0	CC 0 for Option 11, loop & shelf of clock controller for MGCs

For a plain circuit 'bounce' or reset count to 10, and re-enable it.
To remove / replace card, also disable the associated MSDL: DIS MSDL x (MAP DCH to identify MSDL).
If the PRI card has a front panel switch, set it to Dis before removing/inserting card. On inserting, wait 10 seconds: set to Enb.
Check a replacement cards dip switches. UDT cards are generally NOT drop-in swap-able, as they must always be configured.

3 Enable:

Overlay	Commands	Notes
LD 96:	ENL DCH 5	enable d-channel
	STAT DCH 5	confirm d-channel is enabled
LD 60:	ENLL 12	enable loop
	ENL CC 0	CC 0 for Option 11, loop & shelf of clock controller for MGCs
	TRCK PCK	set track 'primary' reference, add loop & shelf for MGCs
	STAT 12	confirm that loop is enabled
LD 96:	ENL AUTO 5	enable auto d-channel recovery (eg, after a line failure)
LD 60:	STAT 12	confirm status

There should now be 3 green lights on the card (if the card has a clock controller), and 30 IDLE channels!
From the STATus output, make sure the REF CLK is enabled, and tracking (may take a few mins) see below.

LD 60:	RCNT 12	reset loop error counters after a reset, use LCNT to list counters...
	LCNT 12	list loop error counters, use to help identify a problem, eg: frame slips

If this procedure doesn't work, try the following:

LD 96: DIS SERV 5 This will prevent PTT DCH service messages from MBSYing the channels.
LD 96: DIS MSDL x (ALL), ENL MSDL x (ALL, FDL) Use MAP DCH and/or STAT MSDL to find x.

If the loop is 'stuck', and you are unable to disable/enable it, try to reset the DCH: in LD 96, enter: RST MSDL 5

If you have problems bringing a PRI back into service, refer to 2.0 Mb PRI Maintenance.

A note about clocks:

Each PRI needs a reference clock, which can be either Tracking or Free-run (non-tracking). With Media Gateways, each shelf (with digital services) requires a clock controller daughter board on one PRI card (often the left most card). Print SYTI (or DDB) in LD 73 to list them. If you're not sure in which physical loop/shelf a PRI is located, print CEQU in LD 22. For an Option 11, the clock is: CC 0

Clock controller comands in LD 60:

ssck l s - check status of clock controller in media gateway: l=loop; s=shelf
enl cc l s / dis cc l s - enable/disable the clock controller in media gateway: l=loop; s=shelf
trck aaa l s (aaa = PCK, SCLK, or FRUN) - track shelf to the primary or secondary reference, or enable free-run.

If you experience excessive slips after a PRI outage (DTA103 errors), its very likely that the clock controller is either disabled, or has switched to free-run, when it should be tracking. It's good practice to always check the clock status after a circuit returns to service.

For more information about UDT card Clock Controllers, refer to UDT E1 T1 Clocks.

Example printouts:

Use STAT in LD 60 to indentify your PRI Loop(s), DCH number(s), and check the circuit status.
The CH31 position shows the associated D-channel number for that loop, in this case DCH 5.

A healthy 'In Service' E1 may look like this:

Loop is enabled, clock in enabled (and tracking), no alarms indicated, all voice channels are idle.

.stat 12

PRI2 LOOP 12 - ENBL          circuit/loop is enabled
REF CLK: ENBL                reference clock is enabled
TRACKING                     loop is tracking the reference clock
SERVICE RESTORE: YES
ALARM STATUS: ACCEPTABLE                                         no alarms
CH 01 - IDLE DID   VOD  *           CH 02 - IDLE DID   VOD  *    all channels are idle
CH 03 - IDLE DID   VOD  *           CH 04 - IDLE DID   VOD  *
CH 05 - IDLE DID   VOD  *           CH 06 - IDLE DID   VOD  *
CH 07 - IDLE DID   VOD  *           CH 08 - IDLE DID   VOD  *
CH 09 - IDLE DID   VOD  *           CH 10 - IDLE DID   VOD  *
CH 11 - IDLE DID   VOD  *           CH 12 - IDLE DID   VOD  *
CH 13 - IDLE DID   VOD  *           CH 14 - IDLE DID   VOD  *
CH 15 - IDLE DID   VOD  *           CH 16 - IDLE DID   VOD  *
CH 17 - IDLE DID   VOD  *           CH 18 - IDLE DID   VOD  *
CH 19 - IDLE DID   VOD  *           CH 20 - IDLE DID   VOD  *
CH 21 - IDLE DID   VOD  *           CH 22 - IDLE DID   VOD  *
CH 23 - IDLE DID   VOD  *           CH 24 - IDLE DID   VOD  *
CH 25 - IDLE DID   VOD  *           CH 26 - IDLE DID   VOD  *
CH 27 - IDLE DID   VOD  *           CH 28 - IDLE DID   VOD  *
CH 29 - IDLE DID   VOD  *           CH 30 - IDLE DID   VOD  *
CH 31 - DCH 5

An 'Out Of Service' E1 may look like this:

A RED alarm on the card face plate, and a LOS 'loss of signal' in STAT indicates a circuit problem (no receive).

.stat 12

PRI2 LOOP 12 - ENBL
REF CLK: DSBL
SERVICE RESTORE: NO
ALARM STATUS: OOS NO AUTO STRT  LOCAL ALARM : LOS  out of service, with loss of signal
CH 01 - MBSY DID   VOD  *           CH 02 - MBSY DID   VOD  *    all channels are down 
CH 03 - MBSY DID   VOD  *           CH 04 - MBSY DID   VOD  *
CH 05 - MBSY DID   VOD  *           CH 06 - MBSY DID   VOD  *
CH 07 - MBSY DID   VOD  *           CH 08 - MBSY DID   VOD  *
CH 09 - MBSY DID   VOD  *           CH 10 - MBSY DID   VOD  *
CH 11 - MBSY DID   VOD  *           CH 12 - MBSY DID   VOD  *
CH 13 - MBSY DID   VOD  *           CH 14 - MBSY DID   VOD  *
CH 15 - MBSY DID   VOD  *           CH 16 - MBSY DID   VOD  *
CH 17 - MBSY DID   VOD  *           CH 18 - MBSY DID   VOD  *
CH 19 - MBSY DID   VOD  *           CH 20 - MBSY DID   VOD  *
CH 21 - MBSY DID   VOD  *           CH 22 - MBSY DID   VOD  *
CH 23 - MBSY DID   VOD  *           CH 24 - MBSY DID   VOD  *
CH 25 - MBSY DID   VOD  *           CH 26 - MBSY DID   VOD  *
CH 27 - MBSY DID   VOD  *           CH 28 - MBSY DID   VOD  *
CH 29 - MBSY DID   VOD  *           CH 30 - MBSY DID   VOD  *
CH 31 - DCH 5