一种适用于小型数字程控交换机的ISDN接口研制
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摘要
LG—300A是我校自主研制并生产的小型数字程控交换机，具有交换、汇接、调度等功能。它采用了数字中继和时分交换技术，实现了传输和交换的数字化，广泛用于机关、企业、工矿等内部通信量大的社会集团。但是LG—300A提供的用户—网络接口仍然是传统的模拟接口，在用户和交换机之间的用户线上数据传输速率至多为9.6kbit／s，由它组成的专用网只能以语音通信为主。随着通信技术的飞速发展，LG—300A和许多用户交换机一样都面临着组成的专用网功能和业务简单，网络整体水平较低等问题。又因为专用网和公共电话网相对独立，一些新业务的引入比较困难，难以满足专用网用户越来越高的需求，因此需要对LG—300A交换机进行升级改造。
本文选择了ISDN(综合业务数字网)交换机作为研制的参考模型，在LG—300A交换机系统上增加了数字用户接口板，每块板上可提供了4个标准的U接口，并依据ITU—T Q.921、Q.931建议，设计了协议处理软件和呼叫处理软件。改造后的交换机可实现端到端的数字连接，使用户线上数据的传输速率增为144kbit／s，由它组成的专用网提供的业务数量大大增加，可提供话音、数据、图像等多种业务，能满足用户日益增加的业务需求。进一步拓宽了LG—300A数字程控交换机的应用范围，增加了它的市场潜力。尤为重要的是，本文的设计具有通用性，基本保持了交换机原有机构，因此可应用到许多其它型号的小型数字程控交换机上。
LG-300A is a small scale digital stored-program-control exchange which is developed and manufactured by our own department. For LG-3 00A having realized digital transmission and digital exchange, it is widely used by many corporations > universities ^ and many other social groups. But LG-300A only offers traditional analog subscriber interface to users, and the data rate transmitted across subscriber line is less than 9.6kbit/s. So the mainly function offered by the private telecommunication networks built up with LG-300A is limited only in voice service fields. With the high developing of telecommunication technology, the private network is faced with many strict problems such as simple functions, comparatively separated from PSTN and can not provide high speed transmission services etc. Now it is very necessary to upgrade the LG-300A's functions to support more and more services and meet the increasing user demands.
This paper chooses ISDN (Integrated Services Digital Network) exchange as reference model and gives the full resolution. On the part of hardware, the new digital subscriber interface board is added to LG-300A and every board has four U-interfaces. On the software we design protocol software and calling processing software based on ITU-T recommendation Q.921 and Q.931. The upgraded exchange realizes end-to-end digital connectivity and increases the data rate to 144kbit/s in the subscriber line. Furthermore the updated private network can offer voice, data, image transmission services. With the high universal characteristic, this resolution keeps the old exchange framework at the most benefits and can be applied to other model small scale digital stored-program-control exchange also.
本文选择了ISDN(综合业务数字网)交换机作为研制的参考模型，在LG—300A交换机系统上增加了数字用户接口板，每块板上可提供了4个标准的U接口，并依据ITU—T Q.921、Q.931建议，设计了协议处理软件和呼叫处理软件。改造后的交换机可实现端到端的数字连接，使用户线上数据的传输速率增为144kbit／s，由它组成的专用网提供的业务数量大大增加，可提供话音、数据、图像等多种业务，能满足用户日益增加的业务需求。进一步拓宽了LG—300A数字程控交换机的应用范围，增加了它的市场潜力。尤为重要的是，本文的设计具有通用性，基本保持了交换机原有机构，因此可应用到许多其它型号的小型数字程控交换机上。
LG-300A is a small scale digital stored-program-control exchange which is developed and manufactured by our own department. For LG-3 00A having realized digital transmission and digital exchange, it is widely used by many corporations > universities ^ and many other social groups. But LG-300A only offers traditional analog subscriber interface to users, and the data rate transmitted across subscriber line is less than 9.6kbit/s. So the mainly function offered by the private telecommunication networks built up with LG-300A is limited only in voice service fields. With the high developing of telecommunication technology, the private network is faced with many strict problems such as simple functions, comparatively separated from PSTN and can not provide high speed transmission services etc. Now it is very necessary to upgrade the LG-300A's functions to support more and more services and meet the increasing user demands.
This paper chooses ISDN (Integrated Services Digital Network) exchange as reference model and gives the full resolution. On the part of hardware, the new digital subscriber interface board is added to LG-300A and every board has four U-interfaces. On the software we design protocol software and calling processing software based on ITU-T recommendation Q.921 and Q.931. The upgraded exchange realizes end-to-end digital connectivity and increases the data rate to 144kbit/s in the subscriber line. Furthermore the updated private network can offer voice, data, image transmission services. With the high universal characteristic, this resolution keeps the old exchange framework at the most benefits and can be applied to other model small scale digital stored-program-control exchange also.
引文
(1)陈建华等，ISDN联网技术与应用指南，清华大学出版社，2001。
(2)乐正友等，程控交换与综合业务通信网，清华大学出版社，1999。
(3)陈锡生等，现代电信交换，北京邮电大学出版社，1999。
(4)叶敏，程控数字交换与现代通信网，北京邮电大学出版社，1998。
(5)深圳市华为技术有限公司，C&C08 数字程控交换系统，人民邮电出版社，1997。
(6)蔡美琴等，MCS—51系列单片机系统及其应用，高等教育出版社，1992。
(7)何立民，MCS—51系列单片机系统设计(系统配置与接口技术)，北京航空航天大学出版社，1990。
(8)乐正友等，程控数字交换机硬件软件及应用，清华大学出版社，1991。
(9)程时端，综合业务数字网，人民邮电出版社，1993。
(10)赵慧玲，综合业务数字网技术及其应用，人民邮电出版社，1995。
(11)唐宝民等，电信网技术基础，人民邮电出版社，2001。
(12)钱志军等，MC145572 ISDN U 接口收发器与 MC145574 ISDN S/T 接口收发器用户手册，人民邮电出版社，1998。
(13)ITU—T Recommendation Q.921: ISDN user-network interface Data link layer specification,1993。
(14)ITU—T Recommendation Q.931: ISDN user-network interface layer 3 specification for basic call control,1993。
(15)MT8980 Digital Switch, Mitel Semiconductor's Digital Switching/Networking Data Book—Issue 10, P 2—3～2—16。
(16)MT8952 HDLC Protocol Controller, Mitel Semiconductor's Digital Switching/Networking Data Book—Issue 10, P 3—61～3—82。
(2)乐正友等，程控交换与综合业务通信网，清华大学出版社，1999。
(3)陈锡生等，现代电信交换，北京邮电大学出版社，1999。
(4)叶敏，程控数字交换与现代通信网，北京邮电大学出版社，1998。
(5)深圳市华为技术有限公司，C&C08 数字程控交换系统，人民邮电出版社，1997。
(6)蔡美琴等，MCS—51系列单片机系统及其应用，高等教育出版社，1992。
(7)何立民，MCS—51系列单片机系统设计(系统配置与接口技术)，北京航空航天大学出版社，1990。
(8)乐正友等，程控数字交换机硬件软件及应用，清华大学出版社，1991。
(9)程时端，综合业务数字网，人民邮电出版社，1993。
(10)赵慧玲，综合业务数字网技术及其应用，人民邮电出版社，1995。
(11)唐宝民等，电信网技术基础，人民邮电出版社，2001。
(12)钱志军等，MC145572 ISDN U 接口收发器与 MC145574 ISDN S/T 接口收发器用户手册，人民邮电出版社，1998。
(13)ITU—T Recommendation Q.921: ISDN user-network interface Data link layer specification,1993。
(14)ITU—T Recommendation Q.931: ISDN user-network interface layer 3 specification for basic call control,1993。
(15)MT8980 Digital Switch, Mitel Semiconductor's Digital Switching/Networking Data Book—Issue 10, P 2—3～2—16。
(16)MT8952 HDLC Protocol Controller, Mitel Semiconductor's Digital Switching/Networking Data Book—Issue 10, P 3—61～3—82。