Specifications

Overview 1-9
HSSI Null Modem Cable
the same 50-pin connectors as the HSSI cable, but uses the pinout listed in Table 1-3. (For
connection and configuration instructions, see the “Attaching a Null Modem Cable to PA-H HSSI
Port Adapters” section on page 8-2.)
Figure 1-12 Null Modem Cable Connectors
Table 1-3 HSSI Null Modem Cable Pinout
Caution
Although the HSSI connector and the HSSI cable are similar to SCSI-II format, they are
not identical. The HSSI cable specification is more stringent than that for the SCSI-II. If a SCSI-II
cable is used instead of a HSSI cable, proper operation cannot be guaranteed.
Signal Name From Pins Direction To Pins Signal Name
RT (Receive Timing) 2, 27 —> 9, 34 TT (Terminal Timing)
CA (DCE available) 3, 28 —> 8, 33 TA (DTE Available)
RD (Receive Data) 4, 29 —> 11, 36 SD (Send Data)
LC (Loopback C) 5, 30 —> 10, 35 LA (Loopback A)
ST (Send Timing) 6, 31 —> 6, 31 ST (Send Timing)
TA (DTE available) 8, 33 —> 3, 28 CA (DCE Available)
TT (Terminal Timing) 9, 34 —> 2, 27 RT (Receive Timing)
LA (Loopback A) 10, 35 —> 5, 30 LC (Loopback C)
SD (Send Data) 11, 36 —> 4, 29 RD (Receive Data)
GND (Ground) 1, 26,
7, 32,
13, 38,
19, 44,
25, 50
1, 26,
7, 32,
13, 38,
19, 44,
25, 50
GND (Ground)
Loopback (not
connected)
12, 37 12, 37 Loopback (not connected)
Not used 14–18,
20–24,
39–43, 45–49
14–18,
20–24,
39–43, 45–49
Not used
H5692