Black Box SME-422 User manual

DSR CTS TXD PWR DCD RTS RXD
SME 422
CUSTOMER
SUPPORT
INFORMATION
Order toll-free in the U.S. 24 hours, 7 A.M. Monday to midnight Friday: 877-877-BBOX
FREE technical support, 24 hours a day, 7 days a week: Call 724-746-5500 or fax [phone]
Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com • E-mail: [email protected]
NOVEMBER 1993
ME101A-R2 ME101AE-R2 ME101-C
ME102A-R2 ME102AE-R2 ME102C-R2
ME103A-R2 ME103AE-R2 ME103C-R2
ME105A-R2 ME105AE-R2
Synchronous Modem Eliminator
SME–422
SME–V.35
SME–530
SME–X.21

FEDERAL COMMUNICATIONS COMMISSION
AND
INDUSTRY CANADA
RADIO FREQUENCY INTERFERENCE STATEMENTS
This equipment generates, uses, and can radiate radio frequency energy
and if not installed and used properly, that is, in strict accordance with the
manufacturer’s instructions, may cause interference to radio communication.
It has been tested and found to comply with the limits for a Class A
computing device in accordance with the specifications in Subpart J of
Part 15 of FCC rules, which are designed to provide reasonable protection
against such interference when the equipment is operated in a commercial
environment. Operation of this equipment in a residential area is likely to
cause interference, in which case the user at his own expense will be required
to take whatever measures may be necessary to correct the interference.
Changes or modifications not expressly approved by the party responsible
for compliance could void the user’s authority to operate the equipment.
This digital apparatus does not exceed the Class A limits for radio noise emission from
digital apparatus set out in the Radio Interference Regulation of Industry Canada.
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites
applicables aux appareils numériques de classe A prescrites dans le Règlement sur le
brouillage radioélectrique publié par Industrie Canada.
TRADEMARKS USED IN THIS MANUAL
UL is a registered trademark of Underwriters Laboratories
Incorporated.
Molex is a registered trademark of Molex Incorporated.
Any other trademarks mentioned in this manual are acknowledged to be the property
of the trademark owners.

SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
Contents
Chapter Page
1. Specifications ............................................................................................... 1
2. Introduction ................................................................................................. 3
2.1 Overview ................................................................................................ 3
2.2 LED Indicators ...................................................................................... 4
2.3 Power Supply ......................................................................................... 5
2.4 Guidelines for Cable Length ................................................................ 5
3. Configuration ............................................................................................... 6
4. Installation .................................................................................................. 19
5. Troubleshooting ........................................................................................ 20
5.1 Calling Black Box ................................................................................ 20
5.2 Shipping and Packaging ..................................................................... 20
Appendix: Connector Pinouts ......................................................................... 21

1
CHAPTER 1: Specifications
System
Requirements — SME–422 card (ME101-C) only: RM011 or
compatible rack;
SME–V.35 card (ME102C-R2) and SME–530 card
(ME103C-R2) only: RM060 or compatible rack
Interface — SME–422: EIA RS-449/RS-422
SME–V.35: CCITT V.35
SME–530: EIA RS-530
SME–X.21: CCITT X.21
Clock — Internal or external from either attached device
(user-selectable)
Data Rate — Any speed up to 1.344 Mbps that evenly divides
2.688 Mbps (user-selectable)*
*Special versions of our SMEs are available that support slightly different ranges of data rates
from the standard model’s. Selected data rates supported by the two most popular specials are
listed in Tables 3-6 and 3-7 on pages 14 and 15. Call our technical support for more information.
Maximum
Distance — Up to 2,000 ft. (609.6 m) on each side, depending on
cable quality and data rate
User Controls — All models: (2) Internal 6-position DIP switches for
selecting the data rate;
All models but SME–V.35: (11) Internal jumpers for
setting various options;
SME–V.35: (5) Internal jumpers for setting various
options
Indicators — (6) LEDs: TXD, RXD, RTS, CTS, DCD or RLSD,
and PWR
Connectors — All models: (1) 5-pin Molex®female: low-voltage
AC power;
Card models (1) 3-position card-edge connector:
Rack power;
1. Specifications

2
SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
SME–422: (2) DB37 female
SME–V.35: (2) 34-pin M-block female
SME–530: (2) DB25 female
SME–X.21: (2) DB37 female; provided with
(2) adapter cables, DB37 male to DB15 female
Power — 120-VAC standalone models:
From wallmount power supply PS146:
Optimal input: 115 VAC, 60 Hz at 100 mA;
Input range: 104 to 127 VAC, 45 to 65 Hz;
Output: 17 VAC CT at 700 mA;
240-VAC standalone models:
From wallmount power supply PS145E:
Optimal input: 230 VAC, 50 Hz at 50 mA;
Input range: 207 to 253 VAC, 45 to 65 Hz;
Output: 17 VAC CT at 700 mA
Card models: From rack’s power-supply interface
All models: Consumption: 7.5 to 13 W
Temperature — 32 to 122˚F (0 to 50˚C)
Humidity — 0 to 95% noncondensing
Enclosure
(Standalone Units) — Plastic
Size — Standalone models: 2.1"H x 8.8"W x 11.5"D
(5.3 x 22.4 x 29.2 cm);
Card models: 7.5"H x 11"D (19.1 x 27.9 cm)
Weight — Standalone models: 2 lb. (0.9 kg);
Card models: 0.9 lb. (0.4 kg)

3
CHAPTER 2: Introduction
2.1 Overview
With a Synchronous Modem Eliminator (SME), you can establish
communication between two synchronous devices (terminals, CPUs, etc.) at
greater distances than would be possible without an SME, without having to
buy a modem or line driver. We offer four different SME models, one for
each of four different synchronous interfaces:
• The SME–422 (our product codes are ME101A-R2 for the 120-VAC
standalone, ME101AE-R2 for the 240-VAC standalone, and ME101-C
for the card version) connects devices that use the RS-422 interface.
• The SME–V.35 (our product codes are ME102A-R2 for the 120-VAC
standalone, ME102AE-R2 for the 240-VAC standalone, and ME102C-R2
for the card version) connects devices that use the CCITT V.35 interface.
• The SME–530 (our product codes are ME103A-R2 for the 120-VAC
standalone, ME103AE-R2 for the 240-VAC standalone, and ME103C-R2
for the card version) connects devices that use the RS-530 interface.
• The SME–X.21 (our product codes are ME105A-R2 for the 120-VAC
standalone and ME105AE-R2 for the 240-VAC standalone) connects
devices that use the CCITT X.21 interface.
Before you install your SME, you’ll have to configure it by setting its internal
straps (jumpers) and switches. Two options are configured with DIP switches:
clock source and data rate. (All SME models except the SME–X.21 can either
provide internal clocking or use an external source. The SME–X.21 uses its
internal clock only. All SME models can be set to use a variety of data rates up
to 1.344 Mbps.) Besides the DIP switches, all SME models have additional
straps for customizing their interface leads.
Once the unit is configured, installation is simple: Run cable from the
devices to connectors J1 and J2 on the rear panel of the SME, then plug in
the SME’s power cord.
Figure 2-1 on the next page shows typical SME applications.
2. Introduction

4
SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
2.2 LED Indicators
The six LED indicators on the front panel of the SMEs function as follows:
2.3.1 T RANSMIT D ATA (TXD)
Lit when the device connected to J1 is sending data.
2.3.2 R ECEIVE D ATA (RXD)
Lit when the device connected to J1 is receiving data.
2.3.3 R EQUEST TO S END (RTS)
Lit when the device connected to J1 raises RTS.
2.3.4 C LEAR TO S END (CTS)
Lit when J1 is clear to send.
Figure 2-1. Typical SME applications.
SME–X.21
MAINFRAME
COMPUTER
MAINFRAME
COMPUTER
Length of Cable;
422 Interface
specified
MAINFRAME
OR MINI
SME-422 REMOTE
CONTROLLER
MINI, OR
MAINFRAME
SME–422, SME–V.35, or
SME–530 ,

5
CHAPTER 2: Introduction
2.3.5 P OWER (PWR)
Lit when power is applied to the unit (that is, when the unit’s power supply
is working and is plugged into a working outlet).
2.3.6 D ATA C ARRIER D ETECT (DCD) OR R ECEIVE L INE S IGNAL D ETECT (RLSD)
SME–422: Lit when the device connected to J1 raises RTS.
SME–V.35: Lit when the device connected to J2 raises RTS.
SME–530: Lit when the device connected to J1 outputs RLSD (DCD).
SME–X.21: Lit when the SME raises Receiver Ready on J1.
2.3 Power Supply
All 120-VAC standalone models of the SME come with UL®listed wallmount
power supply PS146, whose input is rated at 115 VAC/60 Hz. All 240-VAC
standalone models of the SME come with VDE listed wallmount power supply
PS145E, whose input is rated at 230 VAC/50 Hz. The output of both power
supplies is 17 VAC center-tapped at 0.7 amps. Their output connectors, which
you should plug into connector P1 on the SME when you’re ready to finish
the installation, are indexed to help prevent incorrect insertion.
2.4 Guidelines for Cable Lengths
The maximum length of cable you can run between the
SME and either
of the devices you want to attach to it depends on:
• the cabling standards of the interface that your SME uses.
• the data rate you select (higher data rates often require shorter cable
runs).
• noise sources between the SME and the device (cable run too close to
noise sources will not be able to successfully carry data).
Other concerns not mentioned here might also affect the maximum distance
attainable in your application. For additional information, refer to the
published standards for your SME’s interface (EIA RS-422 or RS-530, CCITT
V.35 or X.21).

6
SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
The pages that follow this one contain charts and diagrams that will help you
configure your SME:
• Tables 3-1 through 3-4 discuss the possible settings of the individual straps
(jumpers) inside each SME model. Use the straps to configure several
different options for your SME.
NOTE
Clock timing is supplied to each port (J1 and J2) in the form of a “send timing”
signal (derived from that port’s clock source) and a “receive timing” signal
(derived from the other port’s clock source). The straps that determine how the
SME gets its clock for each port are among those described in Tables 3-1 through
3-4. In the descriptions of these straps, the A position is called “internal,” the B
position is called “recovered,” and the C position is called “external.” When a
port’s timing is internal, the clock is the SME’s internal clock signal. When a port’s
timing is external, the SME gets the clock from that port’s “terminal timing” signal.
When a port’s timing is recovered, the SME gets the clock from the opposite port’s
“terminal timing” signal. For most applications both ports’ straps would be set to
A (internal clock). A small number of applications (those in which one device
supplies the timing across the line) would require one strap set to B and the other
set to C. Extremely few if any applications would require both straps set to C, or
one strap set to C and the other to A. The SME will not work at all if both straps are
set to B, or if one strap is set to B and the other to A. The CCITT X.21 standard
does not include a “terminal timing” signal, so SME–X.21 units won’t work if either
strap is set to B or C.
• Table 3-5 gives the possible settings of the data-rate switches S1 and S2
inside each standard SME model. Use these switches to set the SME’s data
rate to that used in your system. Tables 3-6 and 3-7 show the data-rate
settings for SMEs with special clock modifications (see the notes on pages
1, 14, and 15).
• Figures 3-1 through 3-3 show the printed-circuit-board layout for each
SME model.
Use the appropriate tables and figures to set your SME’s internal straps
and switches (substitute Table 3-6 or 3-7 for Table 3-5 if necessary):
• For the SME–422, use Tables 3-1 and 3-5 and Figure 3-1.
• For the SME–V.35, use Tables 3-2 and 3-5 and Figure 3-2.
• For the SME–530, use Tables 3-3 and 3-5 and Figure 3-3.
• For the SME–X.21, use Tables 3-4 and 3-5 and Figure 3-1.
3. Configuration

7
CHAPTER 3: Configuration
Table 3-1. SME–422 Strap Settings
STRAP FUNCTION
W1 This strap is used to tie the chassis ground and signal ground together.
The unit comes from the factory without the grounds tied common.
W2 Incoming Call (IC) on J1 (Pin 15) is connected to either ground (A-B) or
+5V (B-C). The unit comes from the factory connected to ground (A-B).
W3 Incoming Call (IC) on J2 (Pin 15) is connected to either ground (A-B) or
+5V (B-C). The unit comes from the factory connected to ground (A-B).
W4 In the A-B position, Data Mode on J1 (Pins 11 and 29) is “OFF” and
connected to Terminal Ready (Pins 12 and 30). In the B-C position, Data
Mode is “ON.” The unit is shipped from the factory with Data Mode OFF
(A-B).
W5 In the A-B position, Data Mode on J2 (Pins 11 and 29) is “OFF” and
connected to Terminal Ready (Pins 12 and 30). In the B-C position, Data
Mode is “ON.” The unit is shipped from the factory with Data Mode OFF
(A-B).
W6 Determines the Clear to Send delay on J1:
Position A = 0 ms (no delay)
Position B = 10 ms
Position C = 50 ms
The unit is shipped from the factory with the delay set for 10 ms.
W7 Determines the Clear to Send delay on J2:
Position A = 0 ms (no delay)
Position B = 10 ms
Position C = 50 ms
The unit is shipped from the factory with the delay set for 10 ms.
W8 In the A-B position, Receiver Ready on J2 (Pins 13 and 31) is derived
from Request to Send on J1 (Pins 7 and 25). In the B-C position,
Receiver Ready on J2 is connected to Signal Ground and is constantly
held ON. The unit is shipped from the factory with Receiver Ready
derived from Request to Send (A-B).

8
SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
Table 3-1. SME–422 Strap Settings (cont.)
STRAP FUNCTION
W9 In the A-B position, Receiver Ready on J1 (Pins 13 and 31) is derived
from Request to Send on J2 (Pins 7 and 25). In the B-C position,
Receiver Ready on J1 is connected to Signal Ground and is constantly
held ON. The unit is shipped from the factory with Receiver Ready
derived from Request to Send (A-B).
W10 Determines the clock source for J1 (Pins 5 and 23—Send Timing—on
J1, Pins 8 and 26—Receive Timing—on J2). In the A position, timing is
internal (from the SME’s internal clock). In the B position, timing is
recovered (from J2’s Pins 17 and 35, Terminal Timing). In the C position,
timing is external (from J1’s Pins 17 and 35, Terminal Timing). The unit
is shipped from the factory in the “A,” internal, position. See the note on
page 6.
W10 Determines the clock source for J2 (Pins 5 and 23—Send Timing—on
J2, Pins 8 and 26—Receive Timing—on J1). In the A position, timing is
internal (from the SME’s internal clock). In the B position, timing is
recovered (from J2’s Pins 17 and 35, Terminal Timing). In the C position,
timing is external (from J1’s Pins 17 and 35, Terminal Timing). The unit
is shipped from the factory in the “A,” internal, position. See the note on
page 6.

9
CHAPTER 3: Configuration
Table 3-2. SME–V.35 Strap Settings
STRAP FUNCTION
W1 This strap is used to tie the chassis ground (Pin A) and signal ground
(Pin B) together. The unit comes from the factory without the grounds
tied common.
W2 Sets the Clear to Send delay on J2:
Position A = 0 ms (no delay)
Position B = 10 ms
Position C = 50 ms
The unit is shipped from the factory with the delay set for 10 ms.
W3 Sets the Clear to Send delay on J1:
Position A = 0 ms (no delay)
Position B = 10 ms
Position C = 50 ms
The unit is shipped from the factory with the delay set for 10 ms.
W4 Determines the clock source for J1 (Pins Y and AA—Serial Clock
Transmit—on J1, Pins V and X—Serial Clock Receive—on J2). In the A
position, timing is internal (from the SME’s internal clock). In the B
position, timing is recovered (from J2’s Pins U and W, Serial Clock
Transmit Ext). In the C position, timing is external (from J1’s Pins U and
W, Serial Clock Transmit Ext). The unit is shipped from the factory in the
“A,” internal, position. See the note on page 6.
W5 Determines the clock source for J2 (Pins Y and AA—Serial Clock
Transmit—on J2, Pins V and X—Serial Clock Receive—on J1). In the A
position, timing is internal (from the SME’s internal clock). In the B
position, timing is recovered (from J1’s Pins U and W, Serial Clock
Transmit Ext). In the C position, timing is external (from J2’s Pin U and
W, Serial Clock Transmit Ext). The unit is shipped from the factory in the
“A,” internal, position. See the note on page 6.

10
SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
Table 3-3. SME–530 Strap Settings
STRAP FUNCTION
W1 This strap is used to tie the chassis ground (Pin 1) and signal ground
(Pin 19) together. The unit comes from the factory without the grounds
tied common.
W2 Test Mode (TM) on J1 (Pin 25) is either connected to –5 V (A-B) or +5V
(B-C).
W3 Test Mode (TM) on J2 (Pin 25) is either connected to –5 V (A-B) or +5V
(B-C).
W4 In the A-B position, DCE Ready on J1 (Pins 6 and 22) is “OFF” and
connected to DTE Ready (Pins 20 and 23). In the B-C position, DCE
Ready is “ON.” The unit is shipped from the factory with DCE Ready
OFF (A-B).
W5 In the A-B position, DCE Ready on J1 (Pins 6 and 22) is “OFF” and
connected to DTE Ready (Pins 20 and 23). In the B-C position, DCE
Ready is “ON.” The unit is shipped from the factory with DCE Ready
OFF (A-B).
W6 Sets the Clear to Send delay on J1:
Position A = 0 ms (no delay)
Position B = 10 ms
Position C = 50 ms
The unit is shipped from the factory with the delay set for 10 ms.
W7 Sets the Clear to Send delay on J2:
Position A = 0 ms (no delay)
Position B = 10 ms
Position C = 50 ms
The unit is shipped from the factory with the delay set for 10 ms.
W8 In the A-B position, Received Line Signal Detector (RLSD) on J2 (Pins 8
and 10) is derived from Request to Send on J1 (Pins 4 and 19). In the B-
C position, RLSD on J2 is constantly held ON. The unit comes from the
factory with RLSD derived from Request to Send (A-B).

11
CHAPTER 3: Configuration
Table 3-3. SME–530 Strap Settings (cont.)
STRAP FUNCTION
W9 In the A-B position, Received Line Signal Detector (RLSD) on J1 (Pins 8
and 10) is derived from Request to Send on J2 (Pins 4 and 19). In the B-
C position, RLSD on J1 is constantly held ON. The unit comes from the
factory with RLSD derived from Request to Send (A-B).
W10 Determines the clock source for J1 (Pins 12 and 15—Transmitter Signal
Element Timing DCE—on J1, Pins 9 and 17—Receiver Signal Element
Timing DCE—on J2). In the A position, timing is internal (from the SME’s
internal clock). In the B position, timing is recovered (from J2’s Pins 11
and 24, Transmitter Signal Element Timing DTE). In the C position,
timing is external (from J1’s Pins 11 and 24, Transmitter Signal Element
Timing DTE). The unit is shipped from the factory in the “A,” internal,
position. See the note on page 6.
W11 Determines the clock source for J2 (Pins 12 and 15—Transmitter Signal
Element Timing DCE—on J2, Pins 9 and 17—Receiver Signal Element
Timing DCE—on J1). In the A position, timing is internal (from the SME’s
internal clock). In the B position, timing is recovered (from J1’s Pins 11
and 24, Transmitter Signal Element Timing DTE). In the C position,
timing is external (from J2’s Pins 11 and 24, Transmitter Signal Element
Timing DTE). The unit is shipped from the factory in the “A,” internal,
position. See the note on page 6.

12
SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
Table 3-4. SME–X.21 Strap Settings
STRAP FUNCTION
W1 This strap is used to tie the chassis ground (Pin 1) and signal ground
(DB37 Pin 19, DB15 Pin 8) together. The unit comes from the factory
without the grounds tied common.
(Straps W2 through W7 are not used.)
W8 In the A-B position, Indication (DB37 Pins 13 and 31, DB15 Pins 5 and 12)
on J2 is derived from Control (DB37 Pins 7 and 25, DB15 Pins 3 and 10)
on J1. In the B-C position, Indication on J2 is constantly held ON. The
unit is shipped from the factory with Indication derived from Control
(A-B).
W9 In the A-B position, Indication (DB37 Pins 13 and 31, DB15 Pins 5 and 12)
on J1 is derived from Control (DB37 Pins 7 and 25, DB15 Pins 3 and 10)
on J2. In the B-C position, Indication on J1 is constantly held ON. The
unit is shipped from the factory with Indication derived from Control
(A-B).
W10 Keep this strap set for internal timing on J1 (Position A, the factory-
default setting). The SME’s internal clock is provided on Signal Element
Timing (DB37 Pins 5 and 23, DB15 Pins 6 and 13) on J1 and Byte
Timing (DB37 Pins 8 and 26, DB15 Pins 7 and 14) on J2.
W11 Keep this strap set for internal timing on J2 (Position A, the factory-
default-setting). The SME’s internal clock is provided on Signal Element
Timing (DB37 Pins 5 and 23, DB15 Pins 6 and 13) on J2 and Byte
Timing (DB37 Pins 8 and 26, DB15 Pins 7 and 14) on J1.

13
CHAPTER 3: Configuration
Table 3-5. Data-Rate-Switch Settings, Std. 5.376-MHz Crystal*
DATA SWITCH S1 SWITCH S2
RATE POSITION POSITION
(bps)
123456123456
1200 OFF ON OFF OFF OFF ON ON ON ON ON ON ON
2400 ON OFF OFF OFF ON OFF ON ON ON ON ON OFF
4800 OFF OFF OFF ON OFF OFF ON ON ON ON OFF ON
9600 OFF OFF ON OFF OFF OFF ON ON ON OFF ON OFF
19200 OFF ON OFF OFF OFF OFF ON ON OFF ON OFF OFF
38400 ON OFF OFF OFF OFF OFF ON OFF ON OFF OFF OFF
48000 OFF OFF OFF OFF OFF OFF ON ON ON OFF ON ON
56000 OFF OFF OFF OFF OFF OFF ON ON ON ON OFF ON
64000 OFF OFF OFF OFF OFF OFF ON OFF OFF ON OFF ON
76800 OFF OFF OFF OFF OFF OFF OFF ON OFF OFF OFF ON
84000 OFF OFF OFF OFF OFF OFF ON ON ON ON ON OFF
96000 OFF OFF OFF OFF OFF OFF ON ON OFF ON ON OFF
112000 OFF OFF OFF OFF OFF OFF ON ON ON OFF ON OFF
128000 OFF OFF OFF OFF OFF OFF OFF OFF ON OFF ON OFF
192000 OFF OFF OFF OFF OFF OFF ON OFF ON ON OFF OFF
224000 OFF OFF OFF OFF OFF OFF ON ON OFF ON OFF OFF
336000 OFF OFF OFF OFF OFF OFF ON ON ON OFF OFF OFF
384000 OFF OFF OFF OFF OFF OFF OFF ON ON OFF OFF OFF
448000 OFF OFF OFF OFF OFF OFF ON OFF ON OFF OFF OFF
896000 OFF OFF OFF OFF OFF OFF OFF ON OFF OFF OFF OFF
1344000 OFF OFF OFF OFF OFF OFF ON OFF OFF OFF OFF OFF
*Only the most popular of the speeds that standard SMEs can reach are listed here. The SMEs are capable
of any data rate up to 1.344 Mbps that evenly divides 2.688 Mbps. That is, if you don’t get a remainder when
you divide 2,688,000 bps by your desired speed, the SME can be set to that speed. Call us for technical
support if your desired data rate isn’t shown here.

14
SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
Table 3-6. Data-Rate-Switch Settings, Special 4.9152-MHz Crystal*
DATA SWITCH S1 SWITCH S2
RATE POSITION POSITION
(bps)
123456123456
600 ON ON ON ON ON ON ON ON ON ON ON ON
1200 ON ON ON ON ON OFF ON ON ON ON ON ON
2400 ON ON ON ON OFF OFF ON ON ON ON ON ON
4800 ON ON ON OFF OFF OFF ON ON ON ON ON ON
9600 ON ON OFF OFF OFF OFF ON ON ON ON ON ON
12800 OFF ON OFF OFF OFF OFF ON ON ON ON ON ON
19200 ON OFF OFF OFF OFF OFF ON ON ON ON ON ON
25600 ON OFF OFF OFF OFF OFF ON ON ON ON ON OFF
38400 OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON
51200 OFF OFF OFF OFF OFF OFF ON ON ON ON OFF ON
76800 OFF OFF OFF OFF OFF OFF ON ON ON ON ON OFF
102400 OFF OFF OFF OFF OFF OFF ON ON ON OFF ON OFF
153600 OFF OFF OFF OFF OFF OFF ON ON ON ON OFF OFF
204800 OFF OFF OFF OFF OFF OFF ON ON OFF ON OFF OFF
307200 OFF OFF OFF OFF OFF OFF ON ON ON OFF OFF OFF
409600 OFF OFF OFF OFF OFF OFF ON OFF ON OFF OFF OFF
614400 OFF OFF OFF OFF OFF OFF ON ON OFF OFF OFF OFF
819200 OFF OFF OFF OFF OFF OFF OFF ON OFF OFF OFF OFF
1228800 OFF OFF OFF OFF OFF OFF ON OFF OFF OFF OFF OFF
*To enable them to reach certain normally unsupported speeds, we can modify SMEs at our factory by
swapping in special replacement clock crystals. The major data rates supported by the two most frequently
requested crystals are shown here and on the next page. Only the most popular of the speeds that SMEs with
the 4.9152-MHz customization can reach are listed here. These modified SMEs are capable of any data rate
up to 1.2288 Mbps that evenly divides 2.4576 Mbps. That is, if you don’t get a remainder when you divide
2,457,600 bps by your desired speed, these SMEs can be set to that speed. Call us for technical support if
your desired data rate isn’t shown here.

15
CHAPTER 3: Configuration
Table 3-7. Data-Rate-Switch Settings, Special 6.144-MHz Crystal*
DATA SWITCH S1 SWITCH S2
RATE POSITION POSITION
(bps)
123456123456
1200 ON ON ON OFF OFF ON ON ON ON ON ON ON
2400 ON ON OFF OFF ON OFF ON ON ON ON ON ON
4800 ON OFF OFF ON OFF OFF ON ON ON ON ON ON
9600 OFF OFF ON OFF OFF OFF ON ON ON ON ON ON
19200 OFF ON OFF OFF OFF OFF ON ON ON ON ON OFF
38400 ON OFF OFF OFF OFF OFF ON ON ON ON OFF OFF
48000 OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON
64000 OFF OFF OFF OFF OFF OFF ON ON ON ON OFF ON
76800 OFF OFF OFF OFF OFF OFF ON ON ON OFF OFF ON
96000 OFF OFF OFF OFF OFF OFF ON ON ON ON ON OFF
128000 OFF OFF OFF OFF OFF OFF ON ON ON OFF ON OFF
153600 OFF OFF OFF OFF OFF OFF ON ON OFF OFF ON OFF
192000 OFF OFF OFF OFF OFF OFF ON ON ON ON OFF OFF
256000 OFF OFF OFF OFF OFF OFF ON ON OFF ON OFF OFF
307200 OFF OFF OFF OFF OFF OFF ON OFF OFF ON OFF OFF
384000 OFF OFF OFF OFF OFF OFF ON ON ON OFF OFF OFF
512000 OFF OFF OFF OFF OFF OFF ON OFF ON OFF OFF OFF
614400 OFF OFF OFF OFF OFF OFF OFF OFF ON OFF OFF OFF
768000 OFF OFF OFF OFF OFF OFF ON ON OFF OFF OFF OFF
1024000 OFF OFF OFF OFF OFF OFF OFF ON OFF OFF OFF OFF
1536000 OFF OFF OFF OFF OFF OFF ON OFF OFF OFF OFF OFF
*(See the note on the previous page.) Only the most popular of the speeds that SMEs with the 6.144-MHz
customization can reach are listed here. These modified SMEs are capable of any data rate up to 1.536 Mbps
that evenly divides 3.072 Mbps. That is, if you don’t get a remainder when you divide 3,072,000 bps by your
desired speed, these SMEs can be set to that speed. Call us for technical support if your desired data rate
isn’t shown here.

16
SYNCHRONOUS MODEM ELIMINATORS SME–422, –V.35, –530, –X.21
Figure 3-1. SME–422 and SME–X.21 Printed-Circuit-Board Layout.
PWR CTS TXD DCD RTS RXD
1 5
P1
J1
J2
W3
W2
W11
W4
W5
W10
W8
W7
W9
S2
S1
OFF
6 5 4 3 2 1
A B
CINT
RCVD EXT
W6
C B A
OFF
6 5 4 3 2 1
A B
C
A B
C
A B
C
A B
C
A B
C
A B
C
INT RCVD EXT
1
A B
C
A B
C
W1
Low-voltage
AC Power
DB37
Connector
Data-Rate
Switches
Ribbon
from DB37
Connector
Common
Ground
Tie Point
Rack
Power
FRONT REAR

17
W2
PWR CTS TXD RLSD RTS RXD
J1 J2
W1
Y1
VR1
W4
RCVD
EXT
W5
INT
RCVD
EXT
U3 U16
U5
U6
U7
U8U1
U2
S1
OFF
ON
6 5 4 3 2 1
S2
OFF
ON
U9 U10 U11 U12
U15U14U13
TPI
FOR
TEST ONLY
C1C2
C4C3 CR1
A B
C
W3
A B
C
6 5 4 3 2 1
U4
Low-volatge
AC Power
34-pin
M-block
Connectors
Data-Rate
Switches
Common
Ground
Tie Point
Rack
Power
FRONT REAR
Figure 3-2. SME–V.35 Printed-Circuit-Board Layout.
CHAPTER 3: Configuration