Table of Contents
Advertisement
MTT-14B e_Manual D07-00-083P RevA00
• If the framing and CRC-4 state of the received signal do not
match the framing and CRC-4 settings, the test set will display
Loss of Frame condition and may display loss of CRC DET.
CRC-4
Select yes to measure CRC-4 errors on the incoming signal and
also to transmit the CRC-4 bits on the outgoing signal. CRC-4
works with PCM-31 and PCM-30 framing only. If UNFRAME has
been selected, the CRC-4 configuration is NO.
TEST RATE
Options: 2.048M (F1), Nx64K (F2)
Select an appropriate rate for the circuit under test.
• 2.048M: Configure the test set for full rate testing. If uncertain
about which one to choose, select this for full rate testing.
• Nx64: Configure the test set
for fractional testing. Upon
pressing, the SELECT TIME
SLOT screen is displayed as
in the screen shown to the
right. In it, select each time
slot to test, these can be
selected automatically or
manually using the following
procedures:
Manually Selecting Time Slots
1. Use
to choose the time slot and press SELECT
(F2). Repeat until finished. Selected time slots remain high-
lighted, as shown in Figure 29.
• Press UN-SEL (F3) to deselect a time slot.
• Press CLR-ALL (F4) to clear all selections and to start over.
Automatically Selecting Time Slots
1. Press AUTO (F1) if receiving a signal which is already format-
ted in the Nx64 kbit/s fractional E1 format.
In AUTO, the test set automatically configures time slots by
looking for active data. It will configure the transmit side to
be the same as the active time slots on the receive side. The
test set determines which time slots are active by first deter-
mining which time slots are idle. Any time slot that is not idle
is assumed to be active.
In PCM-31 framing, time slots 1-31 correspond to channels 1-
31. In PCM-30 framing, time slots 1-15 correspond to channels
11:50:50
>LINK DN- Idle
SELECT TIME SLOT
RECEIVE
01
02
03
04
05
09
10
11
12
13
17
18
19
20
21
25
26
27
28
29
TRANSMIT
01
02
03
04
05
09
10
11
12
13
17
18
19
20
21
25
26
27
28
29
AUTO
SELECT
UN-SEL
Figure 29 Select Time Slot Screen
STU-C E1<
06
07
08
14
15
22
23
24
30
31
06
07
08
14
15
22
23
24
30
31
CLR-ALL
Page 49 of 101
Advertisement
Table of Contents
