PEB2085 SIEMENS [Siemens Semiconductor Group], PEB2085 Datasheet - Page 106

• Manufacturer Part Number: PEB2085
• Description: ISDN SubscribernAccess Controller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

2.7
The ISAC-S provides several test and diagnostic functions which can be grouped as follows:
TE/LT-T:
Test loop 3 is activated with the C/I channel command Activate Request Loop (ARL). An S
interface is not required since INFO3 is looped back to the receiver. When the receiver has
synchronized itself to this signal, the message "Test Indication" (or "Awake Test Indication") is
delivered in the C/I channel. No signal is transmitted over the S interface.
In the test loop mode the S interface awake detector is enabled i.e. if a level is detected (e.g.
Info 2/Info 4) this will be reported by the Awake Test Indication (ATI). The loop function is not
effected by this condition and the internally generated 192-kHz line clock does not depend on
the signal received at the S interface.
NT/LT-S:
Test loop 2 is likewise activated over the IOM interface with Activate Request Loop (ARL). No
S line is required. INFO4 is looped back to the receiver and also sent to the S interface. When
the receiver is synchronized, the message "AIU" is sent in the C/I channel. In the test loop
mode the S interface awake detector is disabled, and echo bits are set to logical "0".
Two kinds of test signals may be sent by the ISAC-S: single pulses and continuous pulses.
The single pulses are of alternating polarity, one S interface bit period wide, 0.25 ms apart, with
a repetition frequency of 2 kHz. Single pulses can be sent in all applications. The
corresponding C/I command in TE, LT-S and LT-T applications is SSZ (Send single zeros).
Alternatively, this test mode can be effected by pulling pin SSZ (pin X2, NT mode only) to
logical "0".
Continuous pulses are likewise of alternating polarity, one S-interface bit period wide, but they
are sent continuously. The repetition frequency is 96 kHz. Continuous pulses may be
transmitted in all applications. This test mode is entered in LT-S, LT-T and TE applications with
the C/I command SCZ. Alternatively, pin SCZ (pin CP, NT mode only) can be pulled to logical
"0".
Semiconductor Group
test of layer-2 functions while disabling all layer-1 functions and pins associated with them
(including clocking, in TE mode), via bit TEM (Test Mode in ADF1 register); the ISAC-S is
then fully compatible to the ICC (PEB 2070) seen at the IOM interface. Note that in IOM-1
mode also the internal pull-up resistors at IDP0/1 are disconnected.
digital loop via TLP (Test Loop, SPCR register) command bit: IDP1 is internally connected
with IDP0, output from layer 1 (S/T) on IDP0 is ignored; this is used for testing ISAC-S
functionality excluding layer 1;
loop at the analog end of the S interface;
special loops are programmed via C2C1-0 and C1C1-0 bits (register SPCR)
transmission of special test signals on the S/T interface according to the modified AMI code
are initiated via a C/I command written in CIXR/CIX0 register (cf. chapter 3.4).
Test Functions
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Functional Description