Hi Obinna
Good to see that markets are opening up in Nigeria. Yes you can buy equipment to support your calls. However, one of your considerations would be bandwidth. Quintum A800 would be a good buy. It has 4 pbx and 4 pstn channel/port. you can make 8 simultaneous calls, each call requires 15 – 16kbps 8 x 16 = 128kbps. If you are doing ISDN lines then you must use a buy Digital Quintum. Quintum gateways or any good 8 port gateway start from $1200. You will have to purchase the billing software separately.
If you have further questions email me at tolaniye@hotmail.com
Begra8fl