IBM 3745 Maintenance Information Reference page 257

Transmit Clock Gating by RFS (LICs 1, 2, and 3)
If LlC control register X'02' bit 2 is set for a given line, it allows gating the inter-
face transmit clock by the modem-in lead RFS (despite the clock mode setting).
There is no clock failure reporting if the transmit clock on the interface is
stopped because RFS is OFF.
LIC·4 Personalization
There is only one LlC type 4 part number. LlC type 4A or 48 (personalization)
is defined at IML by the microcode.
LlC 4 "wideband bit", when set, specifies LlC 4A depending on the NCP speed
parameter definition at set mode time.
LIC Wideband with Line Speed Higher than 128 Kbps
The wideband Lie is scanned four times faster than the non-wideband Lie. The
wideband LlC line takes four data slots in the frame.
• With a line speed less than 128 kbps, the four data slots dedicated to the
. Lie in a frame are sufficient for the four lines attached.
• With a line speed higher than 128 kbps, only one line may be attached to
the scanner (the 'high-speed line' bit is set in the control register).
RTS Through DCE or Data Paths
According to the value of modem-out bit 5, the lead RTS of the DeE interface
will change with the new modem-out register or at the boundary of a transmit
data burst as follows:
• RTS through the DCE path:
When modem-out bit 5 is ON, the RTS changes according to the modem-out
bit 1 sent to the LlC by the FESA in even frames.
The RTS change occurs as soon as the new modem-out is loaded.
• RTS through the data path:
When modem-out bit 5 is OFF, the RTS changes according to the value of
bit 0 of the transmit data burst.
The RTS change occurs at the boundary of the transmit burst, that is, with
the last data bit.
LIC Modem-In Process for Non-X.21 Lines
The L1C sends the modem-in information without any process to the FESA. The
FESA then processes this information in order to raise an interrupt to the FES
only with confirmed modem-in information.
For more details see "DCE Lead Management" on page 4-36.
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IBM 3745 Maintenance Information Reference (MIR)